EMC2106-DZK-TR - Microchip Technology

SMSC EMC2106 DATASHEET Revision 1.78 (04-21-09)

Datasheet

PRODUCT FEATURES

EMC2106

Dual RPM-Based Linear Fan

Controller with Hardware

Thermal Shutdown

General Description

The EMC2106 is an SMBus compliant fan controller with

up to five (up to 4 external and 1 internal) temperature

channels. The fan drivers can be operated using two

methods each with two modes. The methods include an

RPM based Fan Speed Control Algorithm and a direct

drive setting. The modes include manually programming

the desired settings or using the internal programmable

temperature look-up table to select the desired setting

based on measured temperature.

The temperature monitors offer 1°C accuracy (for

external diodes) with sophisticated features to reduce

errors introduced by series resistance and beta variation

of substrate thermal diode transistors commonly found

in processors.

The EMC2106 also includes a hardware programmable

temperature limitS and dedicated system shutdown

output for thermal protection of critical circuitry.

Applications

Notebook Computers

Embedded Applications

Projectors

Industrial and Networking Equipment

Features

Two Programmable Fan Control circuits

— 4-wire fan compatible

— High speed PWM (26khz)

— Low speed PWM (9.5Hz - 2240Hz)

— 600mA, 5V, High Side Fan Driver

— Optional detection of aging fans

— 1mA Linear DAC Fan Driver

RPM based fan control algorithm

— 2% accuracy from 500RPM to 16k RPM

Temperature Look-Up Table

— Allows programmed fan response to temperature

— 1 to 4 thermal zones to control each fan driver

— Controls fan speed or drive setting

— Allows externally generated temperature data to control

fan drivers including two DTS channels

Up to Four External Temperature Channels

— Designed to support 45nm, 60nm, and 90nm CPUs

— Automatically detects and supports CPUs requiring the

BJT or Transistor models

— Resistance error correction

— 1°C accurate (60°C to 100°C)

— 0.125°C resolution

— Detects fan aging and variation

Three dedicated comparator outputs for External

Diode 1, External Diode 2, and External Diode 3

(OVERT1#, OVERT2#, OVERT3#)

Up to three thermistor compatible voltage inputs

Hardware Programmable Thermal Shutdown

Temperature

— Cannot be altered by software

— 60°C to 122°C Range or 92°C to 154°C Range

Programmable High and Low Limits for all channels

3.3V Supply Voltage

SMBus 2.0 Compliant

— 2 selectable SMBus addresses

— SMBus Alert compatible

— Option to load register set from external EEPROM

Available in 28-pin QFN package - Lead Free RoHS

compliant (5mm x 5mm)

ORDER NUMBER:

REEL SIZE IS 4,000 PIECES

ORDERING NUMBER PACKAGE FEATURES

EMC2106-DZK 28 pin QFN Lead-Free

RoHS compliant Two independent fa n dri vers (one Hig h Side,

one Linear), up to 4 external diode

measurement channels, one Critical /

Thermal Shutdown input

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

Revision 1.78 (04-21-09) 2 SMSC EMC2106

DATASHEET

80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123

Circuit diagrams and other informa tion relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for

construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC

reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications

before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent

rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated

version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors

known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not

designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property

damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of

this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered

trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.

SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMP LIED WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR P URPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE

OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL

DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;

TORT; NEGLIGENCE OF SMSC OR OTHERS ; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD

TO HAVE FAILED OF ITS E SSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISE D OF THE POSSIBILITY OF SUCH DAMAGES.

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

SMSC EMC2106 3 Revision 1.78 (04-21-09)

DATASHEET

Table of Contents

Chapter 1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Chapter 2 Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 3 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.1 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.2 SMBus Electrical Specifications (client mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3 EEPROM Loader Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Chapter 4 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.1 System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2 Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.3 Read Byte. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.4 Send Byte. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.5 Receive Byte. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.6 Alert Response Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.7 SMBus Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.8 SMBus Time-out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.9 Programming from EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Chapter 5 Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

5.1 Critical/Thermal Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1.1 SHDN_SEL Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.1.2 TRIP_SET / VIN4 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.2 Fan Control Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.3 High Side Fan Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.3.1 Over Current Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.4 Linear DAC Fan Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.5 PWM Fan Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.6 Fan Control Look-Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.6.1 Programming the Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.6.2 DTS Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.7 RPM based Fan Speed Control Algorithm (FSC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.7.1 Programming the RPM Based Fan Speed Control Algorithm . . . . . . . . . . . . . . . . . . . . . 34

5.8 Tachometer Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.8.1 Stalled Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.8.2 32kHz Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5.8.3 Aging Fan or Invalid Drive Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5.9 Spin Up Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5.10 Ramp Rate Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.11 Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

5.12 Internal Thermal Shutdown (TSD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.13 Fault Queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.14 Temperature Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.14.1 Dynamic Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.14.2 Resistance Error Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.14.3 Beta Compensation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.14.4 Digital Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.15 Thermistor Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.16 Diode Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.16.1 Diode Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

Revision 1.78 (04-21-09) 4 SMSC EMC2106

DATASHEET

5.17 GPIOs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.18 Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.19 Over Limit Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Chapter 6 Register Set. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.1 Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.1.1 Lock Entries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6.2 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

6.3 Critical/Thermal Shutdown Temperature Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.4 Pushed Temperature Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

6.5 Voltage Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

6.6 Beta Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.7 REC Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.8 Critical Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.9 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.10 Configuration 2 Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6.11 Configuration 3 Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6.12 Interrupt Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.13 Error Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.13.1 Tcrit Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.14 Fan Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.15 Interrupt Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.16 Fan Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.17 PWM Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.18 PWM Base Frequency Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.19 PWM 3 and 4 Divide Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.20 PWM 3 Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.21 PWM 4 Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

6.22 Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

6.23 Fan Setting Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.24 PWM 1 and 2 Divide Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

6.25 Fan Configuration 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

6.26 Fan Configuration 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.27 Gain Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

6.28 Fan Spin Up Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

6.29 Fan Step Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

6.30 Fan Minimum Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.31 Valid TACH Count Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.32 Fan Drive Fail Band Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.33 TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.34 TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.35 Look Up Table Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.36 Look Up Table 1 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

6.37 Look Up Table 2 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.38 Muxed Pin Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.39 GPIO Direction Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

6.40 GPIO / PWM Pin Output Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

6.41 GPIO Input Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.42 GPIO Output Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.43 GPIO Interrupt Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.44 GPIO Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.45 Software Lock Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.46 Product Features Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.47 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.48 Manufacturer ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

SMSC EMC2106 5 Revision 1.78 (04-21-09)

DATASHEET

6.49 Revision Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Chapter 7 Package Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.1 QFN 28-Pin 5mm x 5mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.2 Package Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Appendix AThermistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

A.1 Thermistor Look Up Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Appendix BLook Up Table Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

B.1 Example #1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

B.1.1 LUT Configuration Bit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

B.2 Example #2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

B.2.1 Configuration 3 Bit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

B.2.2 Fan Configuration 1 Bit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

B.2.3 Fan Spin Up Configuration Bit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

B.2.4 LUT Configuration - Bit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

B.3 Example #3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

B.3.1 Fan Configuration 1 Bit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

B.3.2 Fan Spin Up Configuration Bit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

B.3.3 LUT Configuration - Bit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Chapter 8 Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

Revision 1.78 (04-21-09) 6 SMSC EMC2106

DATASHEET

List of Figures

Figure 1.1 EMC2106 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 2.1 EMC2106 Pin Diagram (28 Pin QFN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 4.1 SMBus Timing Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 5.1 System Diagram of EMC2106 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 5.2 EMC2106 Critical/Thermal Shutdown Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 5.3 Fan Control Look-Up Table Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 5.4 RPM based Fan Speed Control Algorithm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 5.5 Spin Up Routine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 5.6 Ramp Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 5.7 Diode Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 6.1 LOWDRIVE Supported Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 7.1 EMC2106 28-Pin 5x5mm QFN Package Outline and Parameters . . . . . . . . . . . . . . . . . . . . 91

Figure 7.2 EMC2106 Package Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure A.1 “Low Side” Thermistor Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

SMSC EMC2106 7 Revision 1.78 (04-21-09)

DATASHEET

List of Tables

Table 2.1 Pin Description for EMC2106 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 2.2 Pin Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 3.1 Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 3.2 Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 3.3 SMBus Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Table 3.4 EEPROM Loader Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 4.1 Protocol Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 4.2 Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 4.3 Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4.4 Send Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4.5 Receive Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4.6 Alert Response Address Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4.7 ADDR_SEL Pin Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 4.8 Block Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 5.1 SHDN_SEL Pin Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Table 5.2 TRIP_SET Resistor Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Table 5.3 Fan Controls Active for Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Table 5.4 Dynamic Averaging Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Table 6.1 EMC2106 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Table 6.2 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Table 6.3 Temperature Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 6.4 Critical/Thermal Shutdown Temperature Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 6.5 Critical / Thermal Shutdown Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 6.6 Pushed Temperature Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Table 6.7 TripSet Voltage Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Table 6.8 Beta Configuration Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 6.9 Beta Compensation Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 6.10 REC Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 6.11 Limit Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 6.12 Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 6.13 Configuration 2 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 6.14 Fault Queue. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 6.15 Conversion Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 6.16 Configuration 3 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 6.17 Interrupt Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 6.18 Error Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 6.19 Fan Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 6.20 Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 6.21 Fan Interrupt Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 6.22 PWM Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 6.23 PWM Base Frequency Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 6.24 PWM_BASEx[1:0] Bit Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Table 6.25 PWM Divide Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Table 6.26 PWM 3 Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Table 6.27 PWM 4 Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Table 6.28 Limit Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Table 6.29 Fan Driver Setting Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Table 6.30 PWM 1 and 2 Divide Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 6.31 Fan Configuration 1 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 6.32 Range Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 6.33 Minimum Edges for Fan Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 6.34 Update Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 6.35 Fan Configuration 1 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

Revision 1.78 (04-21-09) 8 SMSC EMC2106

DATASHEET

Table 6.36 Derivative Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Table 6.37 Error Range Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Table 6.38 Gain Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Table 6.39 Gain Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Table 6.40 Fan Spin Up Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 6.41 DRIVE_FAIL_CNT[1:0] Bit Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 6.42 Spin Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 6.43 Spin Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Table 6.44 Fan Step Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Table 6.45 Minimum Fan Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 6.46 Valid TACH Count Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 6.47 Fan Drive Fail Band Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Table 6.48 TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Table 6.49 TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 6.50 Look Up Table Configuration Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 6.51 TEMP3_CFG Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Table 6.52 TEMP4_CFG Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Table 6.53 Look Up Table 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Table 6.54 Look Up Table2 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Table 6.55 Muxed Pin Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 6.56 GPIO5_CFG[1:0] Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 6.57 GPIO4_CFG[1:0] Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 6.58 GPIO Direction Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 6.59 GPIO / PWM Pin Output Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 6.60 GPIO Input Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Table 6.61 GPIO Output Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Table 6.62 GPIO Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Table 6.63 GPIO Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 6.64 Software Lock Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 6.65 Product Features Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 6.66 SHDN_SEL Bit Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 6.67 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 6.68 Manufacturer ID Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 6.69 Revision Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Table A.1 “Low Side” Thermistor Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Table A.2 Inverted Thermistor Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Table B.1 Look Up Table Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table B.2 Look Up Table Example #1 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Table B.3 Fan Speed Control Table Example #1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Table B.4 Fan Speed Determination for Example #1 (using settings in Table B.3) . . . . . . . . . . . . . . . . 100

Table B.5 Look Up Table Example #2 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Table B.6 Fan Speed Control Table Example #2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Table B.7 Fan Speed Determination for Example #2 (using settings in Table B.6) . . . . . . . . . . . . . . . . 102

Table B.8 Look Up Table Example #3 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Table B.9 Fan Speed Control Table Example #3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Table B.10Fan Speed Determination for Example #3 (using settings in Table B.9) . . . . . . . . . . . . . . . . 105

Table 8.1 Customer Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

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Chapter 1 Block Diagram

Figure 1.1 EMC2106 Block Diagram

Analog

Mux

External

Temp

Diodes

Internal

Temp

Diode

11 bit Σ Δ

ADC Temp Registers

SMBus

Slave

Protocol

PWM

Drivers

Configuration

DP1

DN1 SMCLK

SMDATA

Temp Limit

Registers

PWM1*

DP2

DN2

OVERT1#*

Thermal

Shutdown

Logic

SYS_SHDN#

Tachs

PWM2*

TACH1

TACH2*

Lookup

Table / RPM

Control

DN4 / DP3*

DP4 / DN3*

CLK_IN*

GPIOs

ADDR_SEL

GPIO2*

GPIO1*

SHDN_SEL

TRIP_SET*

Reference VREF*

Anti-

parallel

diode

OVERT2#*

OVERT3#*

ALERT#

GPIO4*

GPIO3*

GPIO6

GPIO5*

PWM3*

PWM4*

* denotes multiple pin functions

VIN1*

VIN2*

VIN3*

High

Side

Fan

Driver

VDD_5V

FAN_OUT DAC

DAC2*

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Chapter 2 Pin Description

Figure 2.1 EMC2106 Pin Diagram (28 Pin QFN)

EMC2106

28-QFN 5m m x 5mm

DN1 / VIN1 1

DP1 / VREF_T1

TRIP_SET / VIN4

VDD

SMCLK

DN2 / VIN2

DP2 / VREF_T2

DN3 / DP4 / VIN3

DP3 / DN4 / VREF_T3

OVE R T1# / PW M 1

TACH2 / GPIO2

SMDATA

ALERT#

SYS_SHDN#

CLK_IN / GP IO1

SHDN_SEL

ADDR_SEL

TACH1

PWM2 / GPIO3

GND

OVERT3 # / G PIO5 / P WM 4

OVERT2# / GPIO4 / PWM3

GPIO6

DAC2

FAN_OUT

VDD_5V

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Table 2.1 Pin Description for EMC2106

PIN NUMBER

EMC2106 PIN NAME PIN FUNCTION PIN TYPE

1 DN1 / VIN1

DN1 - Negative (cathode) analog input for

External Diode 1 (default) AIO (2V)

VIN1 - General Voltage input to be used

with a thermistor AI (2V)

2 DP1 / VREF_T1

DP1 - Positive (anode) analog input for

External Diode 1 (default) AIO (2V)

VREF_T1 - Reference output for us e with

a thermistor and to drive VIN1 AO (2V)

3 GND Ground Connection Power

4 VDD Power Supply Power

5OVERT3#/ GPIO5/

PWM4

OVERT3# - Active low interrupt for the

External Diode 3 channel

(default) OD (5V)

GPI5 - General Purpose Input DI (5V)

GPO5 - General Purpose push/ pull

Output DO

GPO5 - General Purpose open drain

Output. OD (5V)

PWM4 - Open Drain PWM driver OD (5V)

PWM4 - Push-Pull PWM driver DO

6ALERT#

Active low interrupt - requires external

pull-up resistor. OD (5V)

7 CLK_IN / GPIO1

CLK_IN - 32.768KHz clock input. DI (5V)

GPI1 - General Purpose Input

(default) DI (5V)

GPO1 - General Purpose push/ pull

Output DO

GPO1 - General Purpose open drain

Output. OD (5V)

8OVERT2# / GPIO4 /

PWM3

OVERT2# - Active low Interrupt for the

External Diode 2 channel

(default) OD (5V)

GPI4 - General Purpose Input DI (5V)

GPO4 - General Purpose push/ pull

Output DO

GPO4 - General Purpose open drain

Output. OD (5V)

PWM3 - Open Drain PWM driver OD (5V)

PWM3 - Push-Pull PWM driver DO

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9 SYS_SHDN# Active low Critical System Shutdown

output OD (5V)

10 SMDATA SMBus data input/output - requires

external pull-up resistor DIOD (5V)

11 SMCLK SMBus clock input - requires external

pull-up resistor DIOD (5V)

12 GPIO6

GPI6 - General Purpose Input

(default) DI (5V)

GPO6 - General Purpose push/ pull

Output OD (5V)

GPO6 - General Purpose open drain

Output.) DO

13 PWM2 / GPIO3

PWM2 - Open Drain PWM drive output for

Fan 2 (default) OD (5V)

PWM2 - Push-Pull PWM drive output for

Fan 2 DO

GPI3 - General Purpose Input DI (5V)

GPO3 - General Purpose push-pull

Output DO

GPO3 - General Purpose open drain

Output OD (5V)

14 TACH2 / GPIO2

TACH2 - Tachometer input for Fan 2

(default) DI (5V)

GPI2 - General Purpose Input DI (5V)

GPO2 - General Purpose push-pull

Output DO

GPO2 - General Purpose open drain

Output OD (5V)

15 TACH1 Tachometer input for Fan 1 DI (5V)

16 OVERT1# / PWM1

OVERT1# - Active low interrupt for the

External Diode 1 channel

(default) OD (5V)

PWM1 - Open Drain PWM drive output for

Fan 1 OD (5V)

PWM1 - Push-Pull PWM drive output for

Fan 1 DO

17 FAN_OUT High Side Fan Driver Output Power

18 FAN_OUT High Side Fan Driver Output Power

19 VDD_5V Supply for High Side Fan Driver Power

20 VDD_5V Supply for High Side Fan Driver Power

Table 2.1 Pin Description for EMC2106 (continued)

PIN NUMBER

EMC2106 PIN NAME PIN FUNCTION PIN TYPE

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The pin type are described in detail below. All pins labelled with (5V) are 5V tolerant.

All pin labelled with (2V) should not be exposed to any voltage level greater than 2V.

21 TRIP_SET / VIN4

TRIP_SET - Determines HW Shutdown

temperature features for the hardware

shutdown channel AI (2V)

VIN4 - General voltage input when

Thermal / Critical shutdown disabled AI (2V)

22 SHDN_SEL Determines HW Shutdown temperature

features and measurement channel AIO

23 DAC2 Linear Fan Driver Output AO (2V)

24 DN3 / DP4 / VIN3

DN3 / DP4 - Negative (cathode) analog

input for External Diode 3 and positive

(anode) Analog Input for External Diode 4

(default) AIO (2V)

VIN3 - General voltage input for use with

a thermistor AI (2V)

25 DP3 / DN4 / VREF

DP3 / DN4 - Positive (anode) analog input

for External Diode 3 and negative

(cathode) analog input for External Dio de

4 (default) AIO (2V)

VREF_T3 - Reference output for us e with

a thermistor and to drive VIN3 AO (2V)

26 ADDR_SEL Selects SMBus slave address DIT

27 DN2 / VIN2

DN2 - Negative (cathode) analog input for

External Diode 2 (default) AIO (2V)

VIN2 - General voltage input for use with

a thermistor AI (2V)

28 DP2 / VREF_T2

DP2 - Positive (anode) analog input for

External Diode 2 (default) AIO (2V)

VREF_T2 - Reference output for us e with

a thermistor and to drive VIN2 AO (2V)

Thermal Slug GND Ground Power

Table 2 .2 Pin Types

PIN TYPE DESCRIPTION

Power This pin is used to supply power or ground to the device.

DI Digital Input - this pin is used a s a digital input. This pin is

5V tolerant.

AI Analog Input - this pin is used as an input for analog

signals.

Table 2.1 Pin Description for EMC2106 (continued)

PIN NUMBER

EMC2106 PIN NAME PIN FUNCTION PIN TYPE

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AO Analog Output - this pin is used as an output for analog

signals.

AIO Analog Input / Output - this pin is used as an I/O for analog

signals.

DO Push / Pull Digital Output - this pin is used as a digital

output. It can both source and sink current.

DIOD Digital Input / Open Drain Output this pin is used as an

digital I/O. When it is used as an output, It is open drain

and requires a pull-up resistor. This pin is 5V tolerant.

OD Open Drain Digital Output - this pin is used as a digital

output. It is open drain and re quires a pull-up resistor. This

pin is 5V tolerant.

Table 2.2 Pin Types (continued)

PIN TYPE DESCRIPTION

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Chapter 3 Electrical Specifications

Note: Stresses above those listed could cause permanent damage to the device. This is a stress

rating only and functional operation of the device at any other condition above those indicated

in the operation sections of this specification is not implied. When powering this device from

laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be

exceeded or device failure can result. Some power supplies exhibit voltage spikes on their

outputs when the AC power is switched on or off. In addition, voltage transients on the AC

power line may appear on the DC output. If this possibility exists, it is suggested that a clamp

circuit be used.

Note 3.1 All voltages are relative to ground.

Note 3.2 The Package Power Dissipation specification assumes a recommended thermal via design

consisting of four 12mil vias connected to th e grou nd plane wi th a 2x2mm therma l lan ding.

Note 3.3 Junction to Ambi ent (θJA) is dependent on the design of the thermal vias. Without thermal

vias and a thermal landing, the θJA is approximately 52°C/W including localized PCB

temperature increase.

3.1 Electrical Specifications

Table 3.1 Absolute Maximum Ratings

Voltage on 5V tolerant pins including VDD_5V -0.3 to 6.5 V

Voltage on VDD pin -0.3 to 4 V

Voltage on 2V tolerant pins -0.3 to 2.5 V

Voltage on any other pin to GND -0.3 to VDD + 0.3 V

Package Power Dissipation See Note 3.1 1 up to TA = 85°C W

Junction to Ambient (θJA) See Note 3.2 40 °C/W

Operating Ambient Temperature Range -40 to 85°C °C

Storage Temperature Range -55 to 150 °C

ESD Rating, All Pins, HBM 2000 V

Table 3.2 Electrical Specifications

VDD = 3V to 3.6V, VDD_5V = 4.5V to 5.5V, TA = -40°C to 85°C, all Typical values at TA = 27°C unless otherwise

noted.

CHARACTERISTIC SYMBOL MIN TYP MAX UNIT CONDITIONS

DC Power

Supply Voltage VDD 33.33.6V

Supply Current

(active) IDD 2 3 mA 4 Conversions / second -

Dynamic Averaging Enabled

Fan Drivers enabled at max

PWM frequency

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Supply Current IDD 500 750 uA 1 Conversions / second-

Dynamic Averaging disabled,

Fan Drivers disabled.

Supply Current from

VDD_5V IDD_5 100 uA Fan Driver enabled, No load

current

SMBus Delay tSMB 15 ms Delay from power to first SMBus

communication

Time to First Round

Robin 300 ms

External Temperature Monitors

Temperature

Accuracy ±0.25 ±1 °C 60°C < TDIODE < 110°C

30°C < TDIE < 85°C

±0.5 ±2 °C 0°C < TDIODE < 125°C,

0°C < TDIE < 115°C

Temperature

Resolution 0.125 °C

Diode decoupling

capacitor CFILTER 2200 2700 pF Connected across external

diode, CPU, GPU, or AMD diode

Resistance Error

Corrected RSERIES 100 Ohm Sum of series resistance in both

DP and DN lines

Internal Temperature Monitor

Temperature

Accuracy TDIE ±1 ±2 °C Note 3.4

Temperature

Resolution 0.125 °C

Voltage Measurement

Total Unadjusted

Error TUE 1 % Measured at 3/4 full scale

Reference Voltage VREF 800 mV

Reference Accuracy ΔVREF 1%

PWM Fan Driver

PWM Resolution PWM 256 Steps

PWM Duty Cycle DUTY 0 100 %

High Side Fan Driver

Output High Voltage

from 5V supply VOH_5V VDD_5V

- 0.35 VDD_5

V - 0.3 VI

SOURCE = 600mA, VDD_5V =

Voltage Accuracy ΔVFAN_OUT 1 2 % Measured at 3/4 full scale -

Direct Setting Mode

Table 3.2 Electrical Specifications (continued)

VDD = 3V to 3.6V, VDD_5V = 4.5V to 5.5V, TA = -40°C to 85°C, all Typical values at TA = 27°C unless otherwise

noted.

CHARACTERISTIC SYMBOL MIN TYP MAX UNIT CONDITIONS

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Note 3.4 TDIE refers to the internal die temperature and may not match TA due to self heating of

the device. The internal temperature sensor will return TDIE.

Fan Drive Current ISOURCE 600 mA

Overcurrent Limit IOVER 2800 mA Momentary Current drive at

startup for < 2 seconds

1.5V < FAN_OUT < 3.5V

DC Short Circuit

Current Limit ISHORT 700 mA Sourcing current, Thermal

shutdown not triggered,

FA N_ OU T = 0V

Short circuit delay tDFS 2s

Output Capacitive

Load CLOAD 100 uF ZESR < 100mΩ at 10kHz

Linear DAC Fan Driver

DAC Output High

Voltage VDAC2_OH VDD -

0.2 VI

DAC2 = 1mA current source

DAC Output Low

Voltage VDAC2_OL 0.3 V IDAC2 = -1mA current sink

Output Voltage

Accuracy ΔVDAC2 2 % Measured at 3/4 full scale -

Direct Setting Mode

Fan Drive Current IDAC2 -1 1 mA

RPM Based Fan Controller

Tachometer Range TACH 480 16000 RPM

Tachometer Setting

Accuracy ΔTACH ±1 ±2 % External oscillator 32.768kHz

ΔTACH ±2.5 ±5 % Internal Oscillator

40°C < TDIE < 100°C

Thermal Shutdown

Threshold TSDTH 150 °C

Thermal Shutdown

Hysteresis TSDHYST 50 °C

Digital I/O pins

Input High Voltage VIH 2.0 V

Input Low Voltage VIL 0.8 V

Output High Voltage VOH VDD -

0.4 V4 mA current drive

Output Low Voltage VOL 0.4 V 4 mA current sink

Leakage current ILEAK ±5 uA ALERT and SYS_SHDN pins

Powered and unpowered

Table 3.2 Electrical Specifications (continued)

VDD = 3V to 3.6V, VDD_5V = 4.5V to 5.5V, TA = -40°C to 85°C, all Typical values at TA = 27°C unless otherwise

noted.

CHARACTERISTIC SYMBOL MIN TYP MAX UNIT CONDITIONS

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3.2 SMBus Electrical Specifications (client mode)

Table 3.3 SMBus Electrical Specifications

VDD= 3V to 3.6V, TA = -40°C to 85°C Typical values are at TA = 27°C unless otherwise noted.

CHARACTERISTIC SYMBOL MIN TYP MAX UNITS CONDITIONS

SMBus Interface

Input High Voltage VIH 2.0 V

Input Low Voltage VIL 0.8 V

Output High Voltage VOH VDD

- 0.4 V

Output Low Voltage VOL 0.4 V 4 mA current sink

Input High/Low Current IIH / IIL ±5 uA Powered and unpowered

Input Capacitance CIN 5pF

SMBus Timing

Clock Frequency fSMB 10 400 kHz

Spike Suppression tSP 50 ns

Bus free time Start to

Stop tBUF 1.3 us

Setup Time: Start tSU:STA 0.6 us

Setup Time: Stop tSU:STP 0.6 us

Data Hold Time tHD:DAT 0.6 6 us

Data Setup Time tSU:DAT 0.6 72 us

Clock Low Period tLOW 1.3 us

Clock High Period tHIGH 0.6 us

Clock/Data Fall time tFALL 300 ns Min = 20+0.1CLOAD ns

Clock/Data Rise time tRISE 300 ns Min = 20+0.1CLOAD ns

Capacitive Load CLOAD 400 pF per bus line

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3.3 EEPROM Loader Electrical Specifications

Table 3.4 EEPROM Loader Electrical Specifications

VDD = 3.0V to 3.6V, TA = -40oC - 85oC, Typical values are at TA = 27°C unless otherwise noted

CHARACTERISTIC SYMBOL MIN TYP MAX UNITS CONDITIONS

Interface

Input High/Low Current IIH / IIL -1 1 uA

Hysteresis 420 mV

Input Capacitance CIN 5pF

Output Low Sink Current 4 mA VOL = 0.4V

Timing

Loading Delay tDLY 10 ms Delay after power-up until EEPROM

loading begins. (See Section 4.9.)

Loading Time tLOAD 50 ms

Clock Frequency fSMB 50 kHz

Spike Suppression tSP 50 ns

Bus free time Start to

Stop tBUF 1.3 us

Hold Time: Start tHD:STA 0.6 us

Setup Time: Start tSU:STA 0.6 us

Setup Time: Stop tSU:STO 0.6 us

Data Hold Time tHD:DAT 0.3 us

Data Setup Time tSU:DAT 100 ns

Clock Low Period tLOW 1.3 us

Clock High Period tHIGH 0.6 us

Clock/Data Fall time tFALL 300 ns Min = 20+0.1CLOAD ns

Clock/Data Rise time tRISE 300 ns Min = 20+0.1CLOAD ns

Capacitive Load CLOAD 400 pF per bus line

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Chapter 4 Communications

4.1 System Management Bus Interface Protocol

The EMC2106 communicates with a host controller, such as an SMSC SIO, through the SMBus. The

SMBus is a two-wire serial communication protocol between a computer host and its peripheral

devices. A detailed timi ng diagram is shown in Figure 4.1. Stretching of the SMCLK signal is supported,

however the EMC2106 will not stretch the clock signal.

The EMC2106 powers up as an SMBus client (after loading from EEPROM as applicable).

The EMC2106 contains a single SMBus interface. The SMBus address is determined by the

ADDR_SEL pin (see Section 4.7)The EMC2106 client interfaces are SMBus 2.0 compatible and

support Send Byte, Read Byte, Receive Byte and the Alert Response Address as valid protocols.

These protocols are used as shown below.

All of the below protocols use the convention in Table 4.1.

4.2 Write Byte

The Write Byte is used to write one byte of data to the registers as shown below Table 4.2:

Figure 4.1 SMBus Timing Diagram

Table 4.1 Protocol Format

DATA SENT

TO DEVICE DAT A SENT TO

THE HOST

# of bits sent # of bits sent

Table 4.2 Write Byte Protocol

START SLAVE

ADDRESS WR ACK REGISTER

ADDRESS ACK REGISTER

DATA ACK STOP

0 -> 1 0101_111 0 0 XXh 0 XXh 0 1 -> 0

SMDATA

SMCLK

TLOW

TRISE

THIGH

TFALL

TBUF

THD:STA

PSS - Start Condition P - Stop Condition

THD:DAT TSU:DAT TSU:STA

THD:STA

TSU:STO

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4.3 Read Byte

The Read Byte protocol is used to read one byte of data from the registers as shown in Table 4.3.

4.4 Send Byte

The Send Byte protocol is used to set the internal address register pointer to the correct address

location. No data is transferred during the Send Byte protocol as shown in Table 4.4.

4.5 Receive Byte

The Receive Byte protocol is used to read data from a register when the internal register address

pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads

of the same register as shown in Table 4.5.

4.6 Alert Response Address

The ALERT# output can be used as a processor interrupt or as an SMBus Alert when configured to

operate as an interrupt.

When it detects that the ALERT# pin is asserted, the host will send the Alert Response Address (ARA)

to the general address of 0001_100xb. All devices with active interrupts will respond with their client

address as shown in Table 4.6.

Table 4.3 Read Byte Protocol

START SLAVE

ADDRESS WR ACK Register

Address ACK START Slave

Address RD ACK Register

Data NACK STOP

0 -> 1 0101_111 0 0 XXh 0 0 -> 1 0101_111 1 0 XXh 1 1 -> 0

Table 4.4 Send Byte Protocol

START SLAVE

ADDRESS WR ACK REGISTER

ADDRESS ACK STOP

0 -> 1 0101_111 0 0 XXh 0 1 -> 0

Table 4.5 Receive Byte Protocol

START SLAVE

ADDRESS RD ACK REGISTER DATA NACK STOP

0 -> 1 0101_111 1 0 XXh 1 1 -> 0

Table 4.6 Alert Response Address Protocol

START

ALERT

RESPONSE

ADDRESS RD ACK DEVICE

ADDRESS NACK STOP

0 -> 1 0001_100 1 0 0101_111 1 1 -> 0

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The EMC2106 will respond to the ARA in the following way if the ALERT# pin is asserted.

1. Send Slave Address and verify that full slave address was sent (i.e. the SMBus communication

from the device was not prematurely stopped due to a bus contention event).

2. Set the MASK bit to clear the ALERT# pin.

3. The ARA will NOT affect the OVERT1#, OVERT2#, and OVERT3# pins. These pins will be

asserted as long as the error condition is present. When the error condition is removed, the pins

will be cleared.

4.7 SMBus Address

The EMC2106 SMBus Address is determined by the status of the ADDR_SEL pin as shown in

Table 4.7.

Attempting to communicate with the EMC2106 SMBu s interface with an in valid slave ad dress or invalid

protocol will result in no response from the device and will not affect its register contents.

4.8 SMBus Time-out

The EMC2106 includes an SMBus time-out feature. Following a 30ms period of inactivity on the

SMBus, the device will time-out and reset the SMBus interface. The SMBus Timeout defaults to

enabled and can be disabled by setting the DIS_TO bit in the Configuration 2 register.

4.9 Programming from EEPROM

When configured to load from EEPROM (see Section 4.7), the EMC2106 acts as a simple SMBus

Master to read data from a connected EEPROM using the following procedure.

1. After power-up the EMC2106 waits for 10ms with the SMDATA and SMCLK pins tri-stated.

2. Once the wait period has elapsed, the EMC2106 sends a START signal followed by the 7 bit client

address 1010 _000xb followed by a ‘0b’ and waits for an ACK signal from the EEPROM.

3. When the EEPROM sends the ACK signal, the EMC2106 will send a second start signal and

continue sending the Block Read Command (see Table 4.8) to the same slave address. It reads

256 data bytes from the EEPROM sending an ACK be tween each data byte. When 256 data bytes

have been received, it sends a NACK signal followed by a STOP bit.

4. Resets the device as an SMBus Client with slave address 0101_111xb.

If the EMC2106 does not receive an acknowledge bit from the EEPROM then the following will occur:

1. The ALERT# pin will be asserted and will remain asserted until a Host device initiates

communication with the EMC2106 and reads the Status Register. The ALERT# pin will be de-

asserted after a single Status Register read.

2. The EMC2106 will re set its SMBus protocol as a sla ve interfac e and start operating from the default

conditions with slave address 0101_111xb.

Table 4.7 ADDR_SEL Pin Decode

ADDR_SEL SMBUS ADDRESS FUNCTION

‘0’ (GND) 0101_111xb SMBus Client

‘Z’ (open) 0101_111xb EEPROM Programming

‘1’ (VDD) 0101_110xb SMBus Client

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Note: The shaded columns represent data sent from the EMC2106 to the EEPROM device.

APPLICATION NOTE: It is recommended that the EEPROM that is used be an AT24C02B or equivalent device.

The EEPROM slave address must be 1010_000xb. The device must support a block-read

command, 8-bit addressing, and 8-bit data formatting using a 2-wire bus. The device must

support 3.3V digital switching logic and may not pull the SMCLK and SMDATA pins above

5V. Data must be transmitted MSB first.

APPLICATION NOTE: No other SMBus Master should exist on the SMDATA and SMCLK lines. The presence of

another SMBus Master will cause errors in reading from the EEPROM.

The EEPROM should be loaded to mirror the register set of the EMC2106 with the desired

configuration set. All undefined registers in th e EMC2106 register set should be loaded with 0 0h in the

EEPROM. Likewise, all registers that are read-only in the EMC210 6 register set should be loaded with

00h in the EEPROM.

Because of the interaction between the Fan Control Look-up Tables and the Fan Configuration

these registers at the end of the EEPROM loading cycle.

Table 4.8 Block Read Byte Protocol

START SLAVE

ADDRESS WR ACK Register

Address ACK START SLAVE

ADDRESS RD ACK Register

Data (00h) . . .

0-> 1 0101_111 0 0 00h 0 0 -> 1 0101_111 1 0 XXh

ACK Register

Data (01h) ACK Register

Data (02h) ACK Register

Data (03h) . . . ACK Register

Data (FFh) NACK STOP

0 XXh 0 XXh 0 XXh . . . 0 XXh 1 1 -> 0

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Chapter 5 Product Description

The EMC2106 is an SMBus compliant fan controller with up to four (up to 4 external) temperature

channels. It contains two fan drivers, a High Side fan driver capable of sourcing 600mA from a 5V

supply and a linear DAC fan driver. In addition, the EMC2106 contains up to four (4) PWM outputs

(two of which can be used with the RPM based Fan Speed Control Algorithm). The fan drivers can be

operated using two methods each with two modes. The methods include an RPM based Fan Speed

Control Algorith m and a direct fan drive setting. The mode s include manual ly programming the desi red

settings or using the internal programmable temperature look-up table to select the desired setting

based on measured temperature.

The temperature monitors offer 1°C accuracy (for external diodes) with sophisticated features to

reduce errors introduced b y series resistance and beta variation of substrate thermal diode transistors

commonly found in processors (including support for BJT or transistor model for CPU diodes).

The EMC2106 also includes a hardware programmable temperature limit and dedicated system

shutdown output for thermal protection of critical circuitry. Any of the three temperature channels can

be configured to measure a thermistor or voltage channel using a precision reference voltage for

reduced system complexity.

Figure 5.1 shows a system diagram of the EMC2106.

Figure 5.1 System Diagram of EMC2106

EMC2106

DP1*

DN1*

DP2*

DN2*

CPU

Thermal

diode

Thermal

diode

GPU

3.3V

TRIP_SET*

SMCLK

SMDATA

ALERT#

3.3V

SYS_SHDN#

VDD

TACH1 tachometer

FAN_OUT (2)

32.768KHz Clock

CLK_IN*

3.3V

TACH2* tachometer

DAC2*

3.3V

Drive

Circuit

DP3 / DN4*

DN3 / DN4*

APD

(optional)

0.8V

1.2k

3.3V

KBC

SHDN_SEL

ADDR_SEL

VDD_5V (2)

OVERT1#*

OVERT2#*

OVERT3#*

* denotes other functions available on this pin

GPIO6

GND

GPIO3*

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5.1 Critical/Thermal Shutdown

The EMC2106 provides a hardware Critical/Thermal Shutdown function for systems. Figure 5.2 is a

block diagram of this Critical/Thermal Shutdown function. The Critical/Thermal Shutdown function in

the EMC2106 accepts configuration information from the fixed states of the SHDN_SEL pin as

described in Section 5.1.1.

Each of the software programmed temperature limits can be optionally configured to act as inputs to

the Critical / Ther mal Shutdown independent of the hardware shutdown operation. When confi gured to

operate this way, the SYS_SHDN# pin will be asserted when the temperature meets or exceeds the

limit. The pin will be released when the temperature drops below the limit however the individual status

bits will not be cleared if set (see Section 6.13).

The analog portion of the Critical/Thermal Shutdown function monitors the hardware determined

temperature channel (see Section 5.1.1). This measured temperature is then compared with

TRIP_SET point. This TRIP_SET point is set by the system designer with a single external resistor

divider as described in Section 5.1.2.

The SYS_SHDN# is asserted when the indicated temperature exceeds the temperature threshold

established by the TRIP_SET i nput pin for a nu mber of co nsecutive measurements defined by the fault

queue. If the HW_SHDN output is asserted and the temperature drops below the Thermal / Critical

Shutdown threshold then it will be set to a logic ‘0’ state.

Figure 5.2 EMC2106 Critical/Thermal Shutdown Block Diagram

Voltage

Conversion

SYS_SHDN#

TRIP_SET

External Diode 1

Critical Shutdown Logic

SMBus Traffic

SW_SHDN

C o n fig u r a tio n

VREF

SHDN_SEL

PIN Decode

‘1’

Temperature

Conversion

Sensor

Inte rn a l D io d e

Channel

HW_SHDN

Temperature

Conversion

and Limit

Registers

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5.1.1 SHDN_SEL Pin

The EMC2106 has a ‘strappable’ input (SHDN_SEL) allowing for configuration of the hardware

Critical/Thermal Shutdown input channels. This pin has 3 possible states and is monitored and

decoded by the EMC2106 at power-up . The three possible states are 0 (tied to GND), 1 (tied to 3.3V)

or High-Z (open). The state of this pin determines which external diode configuration is used for the

Critical / Thermal shutdown function.

The different configurations of the SHDN_SEL pin are described in Table 5.1. SHDN_SEL applies only

to the selected temperature channel.

5.1.2 TRIP_SET / VIN4 Pin

The EMC2106’s TRIP_SET / VIN4 pin is an an alog input to the Critical/The rmal Shutdown block which

sets the Thermal Shutdown temperature. The system designer creates a voltage level at the input

through a simple resistor conn ected to GND as shown in Figure 5.1. The value of this resistor is used

to create an input voltage on the TRIP_SET / VIN4 pin which is translated into a temperature ranging

from 60°C to 122°C or 90°C to 152°C as enumerated in Table 5.2.

When the SHDN_SEL pin is pulled to ‘1’ at power up, then the TRIP_SET / VIN4 pin is configured to

measure VIN4 as its primary function. The circuitry will still calculate the thermal / critical shutdown

threshold based o n the voltage and compare this temperature against the Internal Diode temperature.

This will cause the SYS_SHDN# pin to assert if the measured temperature exceeds this threshold.

The device will also compare the measured voltage against the VIN4 High and Low limi ts. This functi on

is not available if SHDN_SEL is set to ‘0’ or ‘High-Z’ at power up.

APPLICATION NOTE: If the SHDN_SEL pin is pulled to ‘1’ at power up and the TRIP_SET / VIN4 pin is intended

for use as a voltage input then the SYS_SHDN# pin should be ignored.

APPLICATION NOTE: If the SHDN_SEL pin is pulled to ‘1’ at power up and the TRIP_SET / VIN4 pin is intended

to be used to set a threshold level then the VIN4 channel should be masked. Furthermore,

the voltage on the pin must be externally generated based on Equation [1]. Do not use

Table 5.2.

APPLICATION NOTE: When used in its TRIP_SET mode (i.e. the SHDN_SEL pin is not set to a logic ‘1’), current

only flows when th e TRIP_SET / VIN4 pin is being moni tored. At all other times, the internal

reference voltage is removed and the TRIP_SET / VIN4 pin will be pulled down to ground.

Table 5.1 SHDN_SEL Pin Configuration

SHDN_SEL FUNCTION

NAME TEMPERATURE MONITORING FEATURES CRITICAL / THERMAL

SHUTDOWN RANGE

0 Intel Transistor

Mode (substrate

PNP)

The external diode 1 channel is configured with

Beta Compensation enabled and Resistance

Error Correction enabled. This mode is ideal

for monitoring a substrate transistor such as an

Intel CPU thermal diode.

High - 92°C to 154°C

High-Z (open) AMD CPU /

Diode Mode The external diode 1 channel is configured with

Beta Compensation disabled and Resistance

Error Correction disabled. This mode is ideal

for monitoring an AMD processor diode or a

2N3904 diode.

Low - 60°C to 122°C

1 Internal The internal diode is linked to the Hardware set

Thermal / Critical shutdown circuitry and the

SYS_SHDN# pin.

Low - 60°C to 122°C

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APPLICATION NOTE: The TRIP_SET / VIN4 pin circuitry is designed to use a 1% resistor externally. Using a 1%

resistor will result in the Thermal / Critical Shutdown temperature being decoded correctly. If

a 5% resistor is used, then the Thermal / Critical Shutdown temperature may be decoded

with as much as ±1°C error.

VTRIP is the TRIP_SET

voltage [1]

TMIN is the minimum

temperature based on the

range

Table 5.2 TRIP_SET Resistor Setting

TTRIP (°C)

LOW RANGE TTRIP (°C)

HIGH RANGE RSET (1%) TTRIP (°C)

LOW RANGE TTRIP (°C)

HIGH RANGE RSET (1%)

60 92 0.0 92 124 1240

61 93 28.7 93 125 1330

62 94 48.7 94 126 1400

63 95 69.8 95 127 1500

64 96 90.9 96 128 1580

65 97 113 97 129 1690

66 98 137 98 130 1820

67 99 158 99 131 1960

68 100 182 100 132 2050

69 101 210 101 133 2210

70 102 237 102 134 2370

71 103 261 103 135 2550

72 104 294 104 136 2740

73 105 324 105 137 2940

74 106 348 106 138 3160

75 107 383 107 139 3480

76 108 412 108 140 3740

77 109 453 109 141 4120

78 110 487 110 142 4530

79 111 523 111 143 4990

80 112 562 112 144 5490

81 113 604 113 145 6040

82 114 649 114 146 6810

VTRIP TTRIP TMIN

–

----------------------------------

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5.2 Fan Control Modes of Operation

The EMC2106 has four modes of operation fo r each fan driver. Each mode of operation uses the Ramp

Rate control and Spin Up Routine.

1. Direct Setting Mode- in this mode of operation, the user directly controls the fan drive setting.

Updating the Fan Driver Setting Register (see Section 6.23) will instantly update the fan drive.

Ramp Rate control is optional and enabled via the EN_RRC bits.

This is the default mode. The Direct Setting Mode is enabled by clearing the LUT_LOCK bit

in the Look Up Table Configuration Register (see Section 6.35) while the TACH / DRIVE bit

is set to ‘0’.

Whenever the Direct Setting Mode is enabled the current drive will be changed to what was

last written into the Fan Driver Setting Register.

2. Fan Speed Control Mode (FSC) - in this mode of operation, the user determines a target

tachometer count and the drive setting is automatically updated to achieve this target speed. The

algorithm uses the Spin Up Routine and has user definable ramp rate controls.

This mode is enabled by clearing the LUT_LOCK bit in the Look Up Table (LUT)

Configuration Register and setting the EN_ALGO bit in the Fan Configuration Register.

3. Using the Look Up Table with Fan Drive Settings (Direct Setting w/ LUT Mode) - In this mode of

operation, the user programs the Look Up Table with fan drive settings and corresponding

temperature thresholds. The fan drive is set based on the measured temperatures and the

corresponding drive settings. Ramp Rate control is optional and enabled via the EN_RRC bits.

This mode is enabled by programming the Look Up Table then setting the LUT_LOCK bit

while the TACH / DRIVE bit is set to ‘1’.

The TACH / DRIVE bit in the Look Up Table Configuration Register MUST be set to ‘1’ or

the fan drive settings will be incorrectly set. Setting this bi t to ‘1’ ensures the settings will be

PWM settings.

4. Using the Lo ok Up Table with RPM Target Settings (FSC w/ LUT Mode) - In this mode of op eration,

the user programs the Look Up Table with TACH Target values and corresponding temperature

thresholds. The TACH Target will be set based on the measured temperatures and the

corresponding target settings. The fan drive settings will be dete rmined automatically based on the

RPM based Fan Speed Control Algorithm.

This mode is enabled by programming the Look Up Table then setting the LUT_LOCK bit

while the TACH / DRIVE bit is set to ‘0’.

83 115 698 115 147 7870

84 116 750 116 148 9090

85 117 787 117 149 10700

86 118 845 118 150 12700

87 119 909 119 151 15800

88 120 953 120 152 20500

89 121 1020 121 153 29400

90 122 1100 122 154 49900

91 123 1150 60 92 Open

Table 5.2 TRIP_SET Resistor Setting (continued)

TTRIP (°C)

LOW RANGE TTRIP (°C)

HIGH RANGE RSET (1%) TTRIP (°C)

LOW RANGE TTRIP (°C)

HIGH RANGE RSET (1%)

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The TACH / DRIVE bit in the Look Up Table Configuration Register MUST be set to ‘0’ or

the TACH Target values will be incorrectly set. Se tting this bit to ‘0’ ensures that the se ttings

will be RPM settings (Tachometer counts).

APPLICATION NOTE: It is important that the TACH Target settings are in the proper format when using the RPM

based Fan Speed Control Algorithm.

5.3 High Side Fan Driver

The EMC2106’s contains a 5V, 600mA, linear high side fan driver to directly drive a 5V fan. By fully

integrating the li near fan driver, the typical requirement for the discrete pass device and other external

linearization circuitry is complete ly eliminated. The linear fan driver is driven by an 8-bit DAC providing

better than 20mV resolution between steps.

5.3.1 Over Current Limit

The High Side Fan Drive r contains circuitry to a llow for significant over current levels to accommo date

transient conditi ons on the FAN pins. The over current limit is dependent upon the output voltage with

the limit dropping as the voltage nears 0V.

Table 5.3 Fan Controls Active for Operating Mode

DIRECT SETTING

MODE FSC MODE DIRECT SETTING W/ LUT

MODE FSC W/ LUT MODE

Fan Driver Setting

(read / write) Fan Driver Setting (read

only) Fan Driver Setting (read

only)

EDGES[1:0] EDGES[1:0]

(Fan Configuration) EDGES[1:0] EDGES[1:0]

- RANGE[1:0]

(Fan Configuration) - RANGE[1:0]

(Fan Configuration)

UPDATE[2:0]

(Fan Configuration) UPDATE[2:0]

(Fan Configuration)

LEVEL

(Spin Up

Configuration)

LEVEL

(Spin Up Configuration) LEVEL

(Spin Up Configuration)

SPINUP_TIME[1:0]

(Spin Up

Configuration)

SPINUP_TIME[1:0]

(Spin Up Configuration) SPINUP_TIME[1:0]

(Spin Up Configuration)

Fan Step Fan Step Fan Step Fan Step

- Fan Minimum Drive Fan Minimum Drive

Valid TACH Count Valid TACH Count Valid TACH Count Valid TACH Count

- TACH Target (read / write) - TACH Target (read

only)

TACH Reading TACH Reading TACH Reading TACH Reading

- - Look Up Table Drive /

Temperature Settings (read

only)

Look up Table Drive /

Temperature Settings

(read only)

- DRIVE_FAIL_CNT[1:0] and

Drive Band Fail Registers - DRIVE_FAIL_CNT[1:0]

and Drive Band Fail

Registers

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If the fan driver current detects a short-circuit condition for longer than 2 seconds, then the I_SHORT

status bit is set and an interrupt generated. Additionally, the High Side Fan Driver will be disabled for

8 seconds. After this 8 second time has elapsed, it will be allowed to restart invoking the Spin Up

Routine before returning to its previous drive setting.

APPLICATION NOTE: If the FSC Algorithm is active, then it will generate errant SPIN_FAIL interrupts during the 8

second time that the fan driver is held off.

5.4 Linear DAC Fan Driver

The EMC2106 contains an internal linear DAC for use as a fan driver. This DAC output voltage has

8-bit resolution from 0V to 3.3V. The linear DAC fan driver is also capable of sourcing and sinking up

to 1 mA of current.

The Linear DAC Fan Driver is biased from the VDD_5V supply and this voltage must be present for

the DAC driver to operate properly.

5.5 PWM Fan Driver

The EMC2106 supports up to four (4) PWM output drivers. Each output driver can be configured to

operate as an open-drain (default) or push-pull driver and each driver can be configured with normal

or inverse polarity. Additionally, the PWM frequencies for PWM1, PWM2, and the two optional PWM

drivers PWM3 and PWM4 are independently programmable with ranges from 9.5Hz to 26kHz in four

programmable frequency bands.

5.6 Fan Control Look-Up Table

The EMC2106 uses a look-up table to apply a user-programmable fan control profile based on

measured temperature to each fan driver. In this look-up table, each temperature channel is allowed

to control the fan drive output independently (or jointly) by programming up to eight pairs of

temperature and drive setting entries.

The user programs the look-up table based on the desired operation. If the RPM based Fan Speed

Control Algorithm is to be used (see Section 5.7), then th e user must program an RPM target for each

temperature setting of interest. Altern ately, if the RPM based Fan Speed Control Algorithm is not to be

used, then the user must program a drive setting for each temperature setting of interest.

If the measured temperature on the External Diode channel meets or exceeds any of the temperature

thresholds for any of the temperature columns (see Appendix B), the fan output will be automatically

set to the desired setting corresponding to the exceeded temperature. In cases where multiple

temperature channel thresholds are exceeded, the highest fan drive setting will take precedence.

When the measured temperat ure drops to a point below a lower threshold minus the hysteresis value,

the fan output will be set to the corresponding lower set point.

Figure 5.3 shows an example of this operation using temperature - drive setting pairs for a single

channel.

See Appendix B for examples of the Look Up Table operation.

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5.6.1 Programming the Look Up Table

When the Look Up Table is used, it must be loaded and configured correctly based on the system

requirements. The following steps outline the procedure.

1. Determine whether the Look Up Table will drive a fan setting or a tachometer target value and set

the TACH / DRIVE bit in the Fan LUT Configuration Register.

2. Determine which measurement channels (up to four) are to be used with the Look Up Table and

set the TEMP3_CFG and TEMP4_CFG bits accordingly in the Fan LUT Configuration Register.

3. For each step to be used in the LUT, set the Fan Se tting (either fan setting or TACH Target as set

by the TACH / DRIVE bit). If a setting is not used, then set it to FFh (if a fan setting) or 00h (if a

TACH Target). Load the lowest settings first in ascending order (i.e. Fan Setting 1 is the lowest

setting greater than “off”. Fan Setting 2 is the next highest setting, etc.).

4. For each step to be used in the LUT, set each of the measurement channel thresholds. These

values must be set in the same data format that the data is presented. If DTS is to be used, then

Figure 5.3 Fan Control Look-Up Table Example

Time

Fan

Setting

Temp

Averaged

Temperature

T4 - Hyst

T5 - Hyst

T6 - Hyst

T3 - Hyst

T2 - Hyst

Measurement taken

Fan

Setting

T7 - Hyst

T8 - Hyst

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the format should be in temperature with a maximum threshold of 100°C (64h). If a measurement

channel is not used, then set the threshold at FFh.

5. Set the Hysteresis value to be smaller than the smallest threshold step.

6. Configure the RPM based Fan Speed Control Algorithm if it is to be used.

7. Set the LUT_LOCK bit to enable the Look Up Table and begin fan control.

5.6.2 DTS Support

The EMC2106 supports DTS (Intel’s Digital Temperature Sensor) data in the Fan Control Look Up

Table. Intel’s DTS data is a positive number that represents the processor ’s relative temperature below

a fixed value called TCONTROL which is generally equal to 100°C for Intel Mobile processors. For

example, a DTS value of 10°C means that the ac tual processor temperature is 10°C below TCONTROL

or equal to 90°C.

Either or both of the Pushed Temperature Registers can be written w ith DTS data and used to control

the respective fan driver. When DTS data is entered, then the USE_DTS_Fx bit must be set in the Fan

LUT Configuration register. Once this bit is set, the DTS data entered is automati cally subtracted from

a value of 100°C. This delta value is then used in the Look Up Table as standard temperature data.

See Appendix B for examples on using DTS data in the Look Up Table.

APPLICATION NOTE: The device is designed with the assumption that TCONTROL is 100°C. As such, all DTS

related conversions are done based on this value including Look Up Table comparisons. If

TCONTROL is adjusted (i.e. TCONTROL is shifted to 105°C), then all of the Look Up Table

thresholds should be adjusted by a value equal to TCONTROL - 100°C.

5.7 RPM based Fan Speed Control Algorithm (FSC)

The EMC2106 includes two RPM based Fan Speed Control Algorithms. Each algorithm operates

independently and controls a separate fan driver. Each algorithm ca n be controlled manually (by setti ng

the target fan speed) or via a look up table.

This fan control algorithm uses Proportional, Integral, and Derivative terms to automatically approach

and maintain the system’s desired fan speed to an accuracy directly proportional to the accuracy of

the clock source. Figure 5.4 shows a simple flow diagram of the RPM based Fan Speed Control

Algorithm operation.

The desired tachometer count is set by the user inputting the desired number of 32.768KHz cycles

that occur per fan revolution. This is done by either manually setting the TACH Target Register or by

programming the Temperature Look-Up Table. The user may change the target count at any time. The

user may also set the target count to FFh in order to disable the fan driver for lower current ope ration.

For example, if a desired RPM rate for a 2-pole fan is 3000 RPMs, then the user would input the

hexidecimal equivalent of 1296 (51h in the TACH Targe t Register). Thi s number represen ts the number

of 32.768KHz cycles that would occur during the time it takes the fan to complete a single revolution

when it is spinning at 3000RPMs.

The EMC2106’s RPM based Fan Speed Control Algorithm has programmable configuration settings

for parameters such as ramp-rate control and spin up conditions. The fan driver automatically detects

and attempts to alleviate a stalled/stuck fan condition while also asserting the ALERT# pin. The

EMC2106 works with fans that operate up to 16,000 RPMs an d provide a valid tachometer signal. The

fan controller will function either with an externally supplied 32.768KHz clock source or with it’s own

internal 32kHz oscillator depending on the required accuracy.

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Figure 5.4 RPM based Fan Speed Control Algorithm

Set TACH Target

Count

TACH

Reading =

TACH

Target?

Spin Up

Required

Perform Spin Up

Routine

M a in t a in F a n D riv e

TACH

Reading <

TACH

Target?

Reduce F an D rive Increase Fan Drive

Measure Fan S peed

Yes

Yes No

Yes

Ra mp Rate C o n t ro l

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5.7.1 Programming the RPM Based Fan Speed Control Algorithm

The RPM based Fan Speed Control Algorithm is disabled upon device power up. The following

registers control the algorithm. The EMC2106 fan control registers are pre-loaded with defaults that

will work for a wide variety of fans so only the TACH Target Register is required to set a fan speed.

The other fan control registers can be used to fine-tune the algorithm behavior based on application

requirements.

Note that steps 1 - 6 are optional and need only be performed if the default settings do not provide

the desired fan response.

1. Set the Spin Up Configuration Register to the Spin Up Level and Spin Time desired.

2. Set the Fan Step Register to the desired step size.

3. Set the Fan Minimum Drive Register to the minimum drive value that will maintain fan operation.

4. Set the Update Time, and Edges options in the Fan Configuration Register.

5. Set the Valid TACH Count Register to the highest tach count that indicates the fan is spinning.

6. Set the TACH Target Register to the desired tachometer count.

7. Enable the RPM based Fan Speed Control Algorithm by setting the EN_ALGO bit.

5.8 Tachometer Measurement

The tachometer measurement circuitry is used in conjunction with the RPM based Fan Speed Control

Algorithm to update the fan driver output. Additionally, it can be used in Direct Setting mode as a

diagnostic for host based fan control.

This method monitors the TACHx signal in real time. It constantly updates the tachometer

measurement by reporting the numb er of clocks between a user programmed number of e dges on the

TACHx signal (see Table 6.33).

The tachometer measurement provides fast response times for the RPM based Fan Speed Control

Algorithm and the data is presented as a count value that represents the fan RPM period. When this

method is used, all fan target values must be input as a count value for proper operation.

APPLICATION NOTE: The tachometer measurement method works independently of the drive settings. If the

device is put into Direct Setting and the fan drive is set at a level that is lower than the fan

can operate (including zero drive), then the tachometer measurement may signal a Stalled

Fan condition and assert an interrupt.

5.8.1 Stalled Fan

A Stalled fan is detected if the tach counter exceeds the user-programmable Valid TACH Count setti ng

then it will flag the fan as stalled and trigger an interrupt.

If the RPM based Fan Speed Control Algorithm is enabled, the algorithm will automatically attempt to

restart the fan until it detects a valid tachometer level or is disabled.

The FAN_STALL Status bit indicates that a stalled fan was detected. This bit is checked conditionally

depending on the mode of operation.

Whenever the Direct Setting Mode or Direct Setting with LUT Mode is enabled or whenever the

Spin Up Routine is enabled, the FAN_STALL interrupt will be masked for the duration of the

programmed Spin Up Time (see Table 6.43) to allow the fan an o pportunity to reach a valid speed

without generating unnecessary interrupts.

In Direct Setting Mode or Direct Setting w/ LUT Mode, and the tachometer measurement is using

the Tach Perio d Measurement method, then whene ver the TAC H Reading Register value exceeds

the Valid TACH Count Register setting, the FAN_STALL status bit will be set.

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When using the RPM based Fan Speed Control Algorithm (either FSC Mode or LUT with FSC

Mode), the stalled fan condition is checked whenever the Update Time is met and the fan drive

setting is updated. It is not a continuous check.

5.8.2 32kHz Clock Source

The EMC2106 allows the user to choose between supplying an external 32.768kHz clock or use of

the internal 32kHz oscillator to measure the tachometer signal. This clock source is used by the RPM

based Fan Speed Control Algorithm to calculate the current fan speed. This fan controller accuracy is

directly proportional to the accuracy of the clock source.

The external clock is provided on the CLK_IN. In order for the external clock to be used, the EXT_CLK

bit must be set in the Configuration Register.

5.8.3 Aging Fan or Invalid Drive Detection

This is useful to detect aging fan conditions (where the fan’s natural maximum speed degrades over

time) or incorrect fa n speed settings.The EMC2106 co ntains circuitry that detects that the programmed

fan speed can be reached by the fan. If the target fan speed cannot be reached within a user defined

band of tach counts at maximum drive then the DRIVE_FAIL status bits are set and the ALERT# pin

is asserted.

5.9 Spin Up Routine

The EMC2106 also contains programmable circuitry to control the spin up behavior of the fan driver

to ensure proper fan operation.

The Spin Up Routine is initiated in Direct Setting mode (with or without the Look Up Table - when

enabled) when the setting value changes from 00h to anything else.

When the Fan Speed Control Alg orithm is enabled, the Spin Up Routine is initiated under the following

conditions when the Tach Period Measurement method of tach measurement is used:

1. The TACH Target Register value changes from a value of FFh to a value that is less than the Valid

TACH Count (see Section 6.31).

2. The RPM based Fan Speed Control Algorithm’s measured TACH Reading Register value i s greater

than the Valid TACH Count setting.

When the Spin Up Routine is operating, the fan driver is set to full scale (optional) for one quarter of

the total user defined spin up time. Fo r the remaining sp in up time, the fan driver ou tput is set a a user

defined level (30% through 65% drive).

After the Spin Up Routine has finished, the EMC2106 measures the TACHx signal. If the measured

TACH Reading Register value is higher than the Valid TACH Count Register setting, the FAN_SPIN

status bit is set and the Spin Up Routine will automatically attempt to restart the fan.

Figure 5.5 shows an example of the Spin Up Routine i n response to a programmed fan speed change

based on the first condition above.

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5.10 Ramp Rate Control

The Fan Driver can be configured with automatic ramp rate control. Ramp rate control is accomplish ed

by adjusting the drive output settings based on the Maximum Fan Step Register settings and the

Update Time settings.

If the RPM based Fan Speed Control Algorithm is used, then this ramp rate control is automatically

used. The user programs a maximum step size for the fan drive setting and an update time. The

update time varies from 100ms to 1.6s while the fan drive maximum step can vary from 1 count to 31

counts.

When a new fan drive setti ng is entered, the delta from the next fan drive setting and th e previous fan

drive setting is determined. If this delta is greater than the Max Step settings, then the fan drive setti ng

is incrementally adjusted every 100ms to 1.6s as determined by the Update Time until the target fan

drive setting is reached. See Figure 5.6.

Figure 5.5 Spin Up Routine

100%

(optional)

30% through 65%

Algorithm controlled drive

Fan Step

Spin Up Time

¼ o f S p in U p T im e

Update Time

Target Count

Changed Target Count

Reached

New Target Count

Prev Target

Count = FFh

Check TACH

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5.11 Watchdog Timer

The EMC2106 contains two internal Watchdog Timers. Once the devi ce has powered up the watchdog

timer monitors the SMBus traffic for signs of activity. The Watchdog Timer starts when the internal

supply has reached its operating point. The Watchdog Timer only starts immediately after power-up

and once it has been triggered or deactivated will not restart.

Each fan driver has an independent watchdog timer. Disabling the watchdog associated with Fan 1

will not disable the watchdog associated with Fan 2.

If four (4) seconds elapse without the system host programming the device, then the watchdog will be

triggered and the following will occur:

1. The WATCH status bit will be set.

2. The fan driver will be set to full scale drive. It will remain at full scale drive until one of the three

conditions listed below are met.

If the Watchdog Timer is triggered, the following three operations will disable the timer and return the

device to normal operation. Alternately, if the Watchdog Timer has not yet been triggered performing

any one of the following will disable it.

1. Writing the Fan Setting Register will disable the Watchdog Timer.

2. Enab ling the RPM based Fan Speed Control Algorithm by setting the EN_ALGO bit will disable the

Watchdog Timer. The fan driver wil l be set based on the RPM ba sed Fan Spee d Control Algorithm.

3. Setti ng the LUT_LOCK bit will disable the Watchdog Timer. The fan driver will be set based on the

Look Up Table settings.

Writing any other configuration registers will not disable the Watchdog Timer.

Figure 5.6 Ramp Rate Control

Setting

Next Desired

Setting

Max

Step

Max

Step

Update

Time Update

Time

S ettin g C h a ng e d

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APPLICATION NOTE: Disabling the Watchdog will not automa tically set the fan driv e. This must be done manually

(or via the Look Up Table).

5.12 Internal Thermal Shutdown (TSD)

The EMC2106 contains an internal the rmal shutdown circuit that monitors the internal die temperature.

If the die temperature exceeds the Thermal Shutdown Threshold (see Table 3.2), then the following

will occur:

1. The High Side Fan Driver is disabled. It will remain disabled until the internal temperature drops

below the threshold temperature minus 50°C.

2. The TSD Status bit will be set and the SYS_SHDN# pin asserted.

3. The SYS_SHDN# pin is asserted.

APPLICATION NOTE: When the fan driver is disabled via a thermal shutdown event, the drive settings will not be

altered. Thus, when the temperature drops below the thre shold minus the hysteresis, the fan

will return to its previous drive setting.

5.13 Fault Queue

The EMC2106 contains a programmable fault queue on all fault conditions except a FAN_SHORT or

TSD condition (including all temperature high, low, and tcrit limits as well as the hardware set thermal

limit). The fault queue defines how many consecutive out-of-limit conditions must be reported before

the corresponding status bit is set (and the ALERT# pin asserted).

APPLICATION NOTE: With the exception of the Tcrit limit, the fault queue is not applied to the internal diode

measurement.

5.14 Temperature Monitoring

The EMC2106 can monitor the temperature of up to four (4) externally connected diodes as well as

the internal or ambie nt temperature. Each channel is configured with the following features enabled or

disabled based on user settings and system requirements.

APPLICATION NOTE: When measuring an Intel 45nm CPU, the reported temperature will have an error of

approximately 1.5°C at 100°C. This error i s related to a non-perfect idea lity factor of th e CPU

diode and is proportional to the diode temperature.

5.14.1 Dynamic Averaging

The EMC2106 supports dynamic averaging. When enabled, this feature changes the conversion time

for all channels based on the se lected conversion rate. This essentially increases the averaging factor

as shown in Table 5.4. The benefits of Dynamic Averaging are improved noise rejection due to the

longer integration time as well as less random variation on the temperature measurement.

Table 5.4 Dynamic Averaging Behavior

CONVERSION RATE

AVERAGING FACTOR (RELATIVE TO 11-BIT CONVERSI0N)

DYNAMIC AVERAGING

ENABLED DYNAMIC AVERAGING

DISABLED

1 / sec 8x 1x

2 / sec 4x 1x

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5.14.2 Resistance Error Correction

The EMC2106 includes active Resistance Error Correction to remove the effect of up to 100 ohms of

series resistance. Without this automatic feature, voltage developed across the parasitic resistance in

the remote diode path causes the temperature to read higher than the true temperature is. The error

induced by parasitic resistance is approximately +0.7°C per ohm. Sources of parasitic resistance

include bulk resistance in the remote temperature transistor junctions, series resistance in the CPU,

and resistance in the printed circu it board traces and package lea ds. Resistance error correction in the

EMC2106 eliminates the need to characterize and compensate for parasitic resistance in the remote

diode path.

5.14.3 Beta Compensation

The forward current gain, or beta, of a transistor is not constant as emitter currents change. As well,

it is not constant over changes in temperature. The variation in beta causes an error in temperature

reading that is proportional to absolute temperature. This correction is done by implementing the BJT

or transistor model for temperature measurement.

For discrete transistors configured with the collector and base shorted together, the beta is generally

sufficiently high such that the percent change in beta variation is very small. For example, a 10%

variation in beta for two forced emitter currents with a tran sistor whose ideal beta is 50 would contribute

approximately 0.25°C error at 100°C. However for substrate transistors where the base-emitte r juncti on

is used for temperature measurement and the collector is tied to the substrate, the proportional beta

variation will cause large error. For example, a 10% variation in beta for two forced emitter currents

with a transistor whose ideal beta is 0.5 would contribute approximately 8.25°C error at 100°C.

The Beta Compensation circuitry in the EMC2106 corrects for this beta variatio n to eliminate any error

which would normally be induced. It automatically detects the appropriate beta setting to use.

5.14.4 Digital Averaging

The External Diode 1 channel support a 4x digital averaging filter. Every cycle, this filter updates the

temperature data based an a running average of the last 4 measured temperature values. The digital

averaging reduces temperature flickering and increases temperature measurement stability.

The digital averaging can be disabled by setting the DIS_AVG bit in the Configuration 2 Register (see

Section 6.10).

5.15 Thermistor Support

The External Diode 1, External Diode 2, and External Diode 3 channels can be configured to monitor

a thermistor. When this function is enabled, the data on the VIN1, VIN2, or VIN3 channels can be

configured to measure a simple voltage input or a ground-connected thermistor circuit (see Appendix

A for more information).

The External Diode 1 channel can only be configured as a voltage input if the SHDN_SEL pin is set

to a logic ‘1’.

4 / sec 2x 1x

8 / sec 1x 1x

Table 5.4 Dynamic Averaging Behavior (continued)

CONVERSION RATE

AVERAGING FACTOR (RELATIVE TO 11-BIT CONVERSI0N)

DYNAMIC AVERAGING

ENABLED DYNAMIC AVERAGING

DISABLED

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5.16 Diode Connections

The diode connection for the External Diode 1 channel is determined at power-up based on the

SHDN_SEL pin (see Section 5.1.1). This channel can support a diode-connected transistor (such as

a 2N3904) or a substrate transistor (such as those found in an CPU or GPU) as shown in Figure 5.7.

The External Diode 3 channel sup ports any diode connection shown or it can be configured to operate

in anti-parallel diode (APD) mode. When configured in APD mode, a fourth temperature channel is

available that shares the DP3 and DN3 pins. When in this mode, both the external diode 3 channel

and external diode 4 channel thermal diodes must be connected as a diode.

5.16.1 Diode Faults

The EMC2106 actively detects an open and short condition on each measurement channel. When a

diode fault is detected, the temperature data MSByte is forced to a value of 80h and the FAULT bit is

set in the Status Register. When the External Diode 3 channel is configured to operate in APD mode,

the circuitry will detect independent open fault conditions, however a short condition will be shared

between the External Diode 3 and External Diode 4 channels.

5.17 GPIOs

The EMC2106 contains up to six (6) GPIO pins (all except GPIO6 are multiplexed with other functions).

The GPIO pins can be individually configured as an input or an output and as a push-pull or open-

drain output. Additionally, each GPIO pin, when configured as an input, can be individually enabled to

trigger an interrupt when they change states.

5.18 Interrupts

If a change of state occurs (such as a temperature out-of-limit condition or a GPIO changing states)

then the following will occur:

1. The appropriate status bits will be set in the Status Register and in the High, Low, and Fault Status

Registers.

2. The ALERT# will be asserted if the specific channel interrupt is enabled (see Section 6.15).

The ALERT# pin is cleared by setting the MASK bit, disabling the specific interrupt channel enable, or

reading the status registers. If the error conditions persist, then the status bits will remain set. Unless

the Interrupt Status Enable bits are cleared or the MASK bit is set, the ALERT# pin will likewise be set.

Figure 5.7 Diode Connections

Local Ground

Typical remote

substrate transistor

i.e. CPU substrate PNP

Typical remote

discrete PNP transistor

i.e. 2N3906

Typical remote

discrete NPN transistor

i.e. 2N3904

Anti-parallel diodes using

discrete NPN transistors

Diode 1Diode 2

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5.19 Over Limit Outputs

The EMC2106 contains three dedicated output pins, OVERT1#, OVERT2#, and OVERT3#. Each of

these pins is dedicated to reporting interrupts associated with the External Diode 1 channel, the

External Diode 2 channel, and the External Diode 3 channel respectively. These interrupts work in

addition to the general interrupt ALERT#.

The OVERT1#, OVERT2#, or OVERT3# pin will be asserted depending on which channel reported an

error condition. These interrupt pins are not masked though they can be individually disabled by the

user.

The OVERT1#, OVERT2# and/or OVERT3# pins are cleared automatically when the measured

temperature drops below the high limit minus 4°C or exceeds the low limit plus 4°C.

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Chapter 6 Register Set

6.1 Register Map

The following registers are accessible through the SMBus Interface. All register bits marked as ‘-’ will

always read ‘0’. A write to these bits will have no effect.

Tab le 6.1 EMC2106 Register Set

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

Temperature Registers

00h R Internal Temp

Reading High

Byte Stores the integer data of the Internal

Diode 00h No Page 54

01h R Internal Temp

Reading Low Byte Stores the fracti onal da ta of the Internal

Diode 00h No Page 54

02h R External Diode 1

Temp Reading

High Byte Stores the integer data of External

Diode 1 and VIN1 channel 00h No Page 54

03h R External Diode 1

Temp Reading

Low Byte Stores the fractional data of External

Diode 1 00h No Page 54

04h R External Diode 2

Temp Reading

High Byte Stores the integer data of External

Diode 2 and VIN2 channel 00h No Page 54

05h R External Diode 2

Temp Reading

Low Byte Stores the fractional data of External

Diode 2 00h No Page 54

06h R External Diode 3

Temp Reading

High Byte Stores the integer data of External

Diode 3 and VIN3 channel 00h No Page 54

07h R External Diode 3

Temp Reading

Low Byte Stores the fractional data of External

Diode 3 00h No Page 54

08h R External Diode 4

Temp Reading

High Byte Stores the integer data of External

Diode 4 00h No Page 54

09h R External Diode 4

Temp Reading

Low Byte Stores the fractional data of External

Diode 4 00h No Page 54

0Ah R Critical/Thermal

Shutdown

Temperature

Stores the calculated Critical/Thermal

Shutdown temperature high limit

derived from the voltage on TRIP_SET

/ VIN4

7Fh

(+127°C) No Page 55

0Ch R/W Pushed

Temperature 1 Stores the integer data for Pushed

Temperature 1 to drive LUT 1 00h No Page 56

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0Dh R/W Pushed

Temperature 2 Stores the integer data for Pushed

Temperature 2 to drive LUT 1 00h No Page 56

0Eh R/W Pushed

Temperature 3 Stores the integer data for Pushed

Temperature 3 to drive LUT2 00h No Page 56

0Fh R/W Pushed

Temperature 4 Stores the integer data for Pushed

Temperature 4 to drive LUT2 00h No Page 56

10h R Trip Set Voltage Stores the raw measured TRIP_SET

voltage or the VIN4 analog vo ltage input FFh No Page 56

Diode Configuration

14h R/W External Diode 1

Beta

Configuration Configures the beta compensation

settings for External Diode 1 10h SWL Page 57

15h R/W External Diode 2

Beta

Configuration Configures the beta compensation

settings for External Diode 2 10h SWL Page 57

16h R/W External Diode 3

Beta

Configuration Configures the beta compensation

settings for External Diode 3 10h SWL Page 57

17h R/W External Diode

REC

Configuration

Configures the Resistance Error

Correction functionality for all external

diodes 07h SWL Page 58

19h R/W External Diode 1

Tcrit Li mi t Stores the Critical temperature limit for

the External Diode 1 64h

(100°C) Write

Lock Page 59

1Ah R/W External Diode 2

Tcrit Li mi t Stores the Critical temperature limit for

the External Diode 2 64h

(100°C) Write

Lock Page 59

1Bh R/W External Diode 3

Tcrit Li mi t Stores the Critical temperature limit for

the External Diode 3 64h

(100°C) Write

Lock Page 59

1Ch R/W External Diode 4

Tcrit Li mi t Stores the Critical temperature limit for

the External Diode 4 64h

(100°C) Write

Lock Page 59

1Dh R/W Internal Diode

Tcrit Li mi t Stores the Critical temperature limit for

the Internal Diode 64h

(100°C) Write

Lock Page 59

Configuration and control

1Fh R-C Tcrit Limit Status Stores the status bits for all temperature

channel Tcrit limits 00h No Page 62

20h R/W Configuration Configures the Thermal / Critical

Shutdown masking options and

software lock 00h SWL Page 59

21h R/W Configuration 2 Controls the conversion rate for

monitoring of all channels 0Eh SWL Page 60

22h R/W Configuration 3 Controls the VIN1 - 3 channels 00h SWL Page 61

23h R Interrupt Status Stores the status bits for temperature

channels 00h No Page 62

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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24h R-C High Limit Status Stores the status bits for all temperature

channel high limits 00h No Page 63

25h R-C Low Limit Status S tores the status bits for all temperature

channel low limits 00h No Page 63

26h R-C Diode Fault Stores the status bits for all temperature

channel diode faults 00h No Page 63

27h R-C Fan Status Stores the status bits for the RPM

based Fan Speed Control Algorithm 00h No Page 64

28h R/W Interrupt Enable

temperature channels 00h No Page 64

29h R/W Fan Interrupt

Enable Register Controls the masking of interrupts on all

fan related channels 00h No Page 65

2Ah R/W PWM Config Configures all PWM drivers 00h No Page 66

2Bh R/W PWM Base

Frequency Selects the base frequency for all PWM

drivers. FFh No Page 66

2Ch R/W PWM 3

Frequency divi de Determines the frequency divide value

for PWM driver 3 if enabled 50h

(80) No Page 67

2Dh R/W PWM3 Setting S tore s the set ti ng of the PWM3 ou tpu t if

enabled 00h No Page 67

2Eh R/W PWM4 Setting Stores the settin g of the PWM4 out put if

enabled 00h No Page 68

2Fh R/W PWM4 Frequency

Divide Determines the frequency divide value

for PWM driver 3 if enabled 50h

(80) No Page 67

Temperature Limit Registers

30h R/W External Diode 1

Temp High Limit High limit for External Diode 1 or VIN1 55h

(+85°C) SWL Page 68

31h R/W External Diode 2

Temp High Limit High limit for External Diode 2 or VIN2 55h

(+85°C) SWL Page 68

32h R/W External Diode 3

Temp High Limit High limit for External Diode 3 or VIN3 55h

(+85°C) SWL Page 68

33h R/W External Diode 4

Temp High Limit High Limit for External Diode 4 55h

(85°C) SWL Page 68

34h R/W Internal Diode

High Limit High Limit for Internal Diode 55h

(85°C) SWL Page 68

35h R/W Voltage 4 High

Limit High Limit for the Voltage 4 channel FFh

(0.8V) SWL Page 68

38h R/W External Diode 1

Temp Low Limit Lo w Limit for External Diode 1 or VIN1 00h

(0°C) SWL Page 68

39h R/W External Diode 2

Temp Low Limit Lo w Limit for External Diode 2 or VIN2 00h

(0°C) SWL Page 68

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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3Ah R/W External Diode 3

Temp Low Limit Lo w Limit for External Diode 3 or VIN3 00h

(0°C) SWL Page 68

3Bh R/W External Diode 4

Temp Low Limit Low Limit for External Diode 4 00h

(0°C) SWL Page 68

3Ch R/W Internal Diode

Low Limit Low Limit for Internal Diode 00h

(0°C) SWL Page 68

3Dh R/W Voltage 4 Low

Limit Low limit for Voltage 4 Channel 00h

(0V) SWL Page 68

Fan 1 Control Registers

40h R/W Fan 1 Setting

Always displays the most recent fan

driver input setting for Fan 1. If the RPM

based Fan Speed Control Algorithm is

disabled, allows direct user control of

the fan driver.

00h No Page 69

41h R/W PWM 1 Divide Stores the divide ratio to set the

frequency for Fan 1 01h No Page 70

42h R/W Fan 1

Configuration 1 Sets configuration values for the RPM

based Fan Speed Co ntrol Algorithm for

the Fan 1 driver 2Bh No Page 70

43h R/W Fan 1

Configuration 2 Sets additional configu ration values for

the Fan 1 driver 38h SWL Page 72

45h R/W Gain 1 Holds the gain terms used by the RPM

based Fan Speed Co ntrol Algorithm for

the Fan 1 driver 2Ah SWL Page 74

46h R/W Fan 1 Spin Up

Configuration Sets the configuration values for Spin

Up Routine of the Fan 1 driver 19h SWL Page 75

47h R/W Fan 1 Step Sets the maximum change per update

for the Fan 1 driver 10h SWL Page 76

48h R/W Fan 1 Minimum

Drive Sets the minimum drive value for the

Fan 1 driver 66h

(40%) SWL Page 77

49h R/W Fan 1 Valid TACH

Count Holds the minimu m tachometer reading

that indicates the fan is spinning

properly F5h SWL Page 77

4Ah R/W Fan 1 Drive Fail

Band Low Byte Store s the number of Tach counts used

to determine how the actual fan speed

must match the target fan speed at fu ll

scale drive

00h SWL Page 78

4Bh R/W Fan 1 Drive Fail

Band High Byte 00h SWL

4Ch R/W TACH 1 Target

Low Byte Holds the target tachometer reading low

byte Fan 1 F8h No Page 78

4Dh R/W TACH 1 Target

High Byte Holds the target tachometer reading

high byte for Fan 1 FFh No Page 78

4Eh R TACH 1 Reading

High Byte Holds the tachometer reading high byte

for Fan 1 FFh No Page 79

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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4Fh R TACH 1 Reading

Low Byte Holds the tachometer reading low byte

for Fan 1 F8h No Page 79

Look Up Table 1 (LUT1)

50h R/W LUT 1

Configuration S tores and controls the configuration for

LUT 1 00h No Page 80

51h R/W LUT 1 Drive 1 Stores the lowest programmed drive

setting for LUT 1 FBh LUT

Lock 1 Page 82

52h R/W LUT 1 Temp 1

Setting 1 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 1 value 7Fh

(127°C) LUT

Lock 1 Page 82

53h R/W LUT 1 Temp 2

Setting 1 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 1 value 7Fh

(127°C) LUT

Lock 1 Page 82

54h R/W LUT 1 Temp 3

Setting 1

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 1

value

7Fh

(127°C) LUT

Lock 1 Page 82

55h R/W LUT 1 Temp 4

Setting 1

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 1 value

7Fh

(127°C) LUT

Lock 1 Page 82

56h R/W LUT 1 Drive 2 Stores the second programmed drive

setting for LUT 1 E6h LUT

Lock 1 Page 82

57h R/W LUT 1 Temp 1

Setting 2 Stores the threshold level for the

External Diode 1 (or VIN1)chan nel that

is associated with the Drive 2 value 7Fh

(127°C) LUT

Lock 1 Page 82

58h R/W LUT 1 Temp 2

Setting 2 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 2 value 7Fh

(127°C) LUT

Lock 1 Page 82

59h R/W LUT 1 Temp 3

Setting 2

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 2

value

7Fh

(127°C) LUT

Lock 1 Page 82

5Ah R/W LUT 1 Temp 4

Setting 2

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 2 value

7Fh

(127°C) LUT

Lock 1 Page 82

5Bh R/W LUT 1 Drive 3 Stores the third programmed drive

setting for LUT 1 D1h LUT

Lock 1 Page 82

5Ch R/W LUT 1 Temp 1

Setting 3 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 3 value 7Fh

(127°C) LUT

Lock 1 Page 82

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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5Dh R/W LUT 1 Temp 2

Setting 3 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 3 value 7Fh

(127°C) LUT

Lock 1 Page 82

5Eh R/W LUT 1 Temp 3

Setting 3

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 3

value

7Fh

(127°C) LUT

Lock 1 Page 82

5Fh R/W LUT 1 Temp 4

Setting 3

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 3 value

7Fh

(127°C) LUT

Lock 1 Page 82

60h R/W LUT 1 Drive 4 Stores the fourth programmed drive

setting for LUT 1 BCh LUT

Lock 1 Page 82

61h R/W LUT 1 Temp 1

Setting 4 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 4 value 7Fh

(127°C) LUT

Lock 1 Page 82

62h R/W LUT 1 Temp 2

Setting 4 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 4 value 7Fh

(127°C) LUT

Lock 1 Page 82

63h R/W LUT 1 Temp 3

Setting 4

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 4

value

7Fh

(127°C) LUT

Lock 1 Page 82

64h R/W LUT 1 Temp 4

Setting 4

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 4 value

7Fh

(127°C) LUT

Lock 1 Page 82

65h R/W LUT 1 Drive 5 Stores the fifth programmed drive

setting for LUT 1 A7h LUT

Lock 1 Page 82

66h R/W LUT 1 Temp 1

Setting 5 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 5 value 7Fh

(127°C) LUT

Lock 1 Page 82

67h R/W LUT 1 Temp 2

Setting 5 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 5 value 7Fh

(127°C) LUT

Lock 1 Page 82

68h R/W LUT 1 Temp 3

Setting 5

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 5

value

7Fh

(127°C) LUT

Lock 1 Page 82

69h R/W LUT 1 Temp 4

Setting 5

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 5 value

7Fh

(127°C) LUT

Lock 1 Page 82

6Ah R/W LUT 1 Drive 6 Stores the sixth programmed drive

setting for LUT 1 92h LUT

Lock 1 Page 82

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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6Bh R/W LUT 1 Temp 1

Setting 6 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 6 value 7Fh

(127°C) LUT

Lock 1 Page 82

6Ch R/W LUT 1 Temp 2

Setting 6 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 6 value 7Fh

(127°C) LUT

Lock 1 Page 82

6Dh R/W LUT 1 Temp 3

Setting 6

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 6

value

7Fh

(127°C) LUT

Lock 1 Page 82

6Eh R/W LUT 1 Temp 4

Setting 6

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 6 value

7Fh

(127°C) LUT

Lock 1 Page 82

6Fh R/W LUT 1 Drive 7 Stores the seventh programmed drive

setting for LUT 1 92h LUT

Lock 1 Page 82

70h R/W LUT 1 Temp 1

Setting 7 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 7 value 7Fh

(127°C) LUT

Lock 1 Page 82

71h R/W LUT 1 Temp 2

Setting 7 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 7 value 7Fh

(127°C) LUT

Lock 1 Page 82

72h R/W LUT 1 Temp 3

Setting 7

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 7

value

7Fh

(127°C) LUT

Lock 1 Page 82

73h R/W LUT 1 Temp 4

Setting 7

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 7 value

7Fh

(127°C) LUT

Lock 1 Page 82

74h R/W LUT 1 Drive 8 Stores the highest programmed drive

setting for LUT 1 92h LUT

Lock 1 Page 82

75h R/W LUT 1 Temp 1

Setting 8 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 8 value 7Fh

(127°C) LUT

Lock 1 Page 82

76h R/W LUT 1 Temp 2

Setting 8 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 8 value 7Fh

(127°C) LUT

Lock 1 Page 82

77h R/W LUT 1 Temp 3

Setting 8

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 1

temp) that is associated with the Drive 8

value

7Fh

(127°C) LUT

Lock 1 Page 82

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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SMSC EMC2106 49 Revision 1.78 (04-21-09)

DATASHEET

78h R/W LUT 1 Temp 4

Setting 8

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 2 temp) that is associated with the

Drive 8 value

7Fh

(127°C) LUT

Lock 1 Page 82

79h R/W LUT 1 Temp

Hysteresis Stores the hysteresis that is shared for

all temperature inputs 0Ah

(10°C) LUT

Lock 1 Page 82

Fan 2 Control Registers

80h R/W Fan 2 Setting

Always displays the most recent fan

driver input setting for Fan 2. If the RPM

based Fan Speed Control Algorithm is

disabled, allows direct user control of

the fan driver.

00h No Page 69

81h R/W PWM2 Divide Stores the divide ratio to set the

frequency for Fan 2 01h No Page 70

82h R/W Fan 2

Configuration1 Sets configuration values for the RPM

based Fan Speed Co ntrol Algorithm for

Fan 2 2Bh No Page 70

83h R/W Fan 2

Configuration 2 Sets additional configu ration values for

the Fan 2 driver 38h SWL Page 72

85h R/W Gain 2 Holds the gain terms used by the RPM

based Fan Speed Co ntrol Algorithm for

Fan 2 2Ah SWL Page 74

86h R/W Fan 2 Spin Up

Configuration Sets the configuration values for Spin

Up Routine of the Fan 2 driver 19h SWL Page 75

87h R/W Fan 2 Step Sets the maximum change per update

for Fan 2 10h SWL Page 76

88h R/W Fan 2 Minimum

Drive Sets the minimum drive value for the

Fan 2 driver 66h

(40%) SWL Page 77

89h R/W Fan 2 Valid TACH

Count Holds the minimu m tachometer reading

that indicates the fan is spinning

properly F5h SWL Page 77

8Ah R/W Fan 2 Drive Fail

Band Low Byte Store s the number of Tach counts used

to determine how the actual fan speed

must match the target fan speed at fu ll

scale drive

00h SWL Page 78

8Bh R/W Fan 2 Drive Fail

Band High Byte 00h SWL

8Ch R/W TACH 2 Target

Low Byte Hold s the target tachometer setting low

byte for Fan 2 F8h No Page 78

8Dh R/W TACH 2 Target

High Byte Holds the target tachometer setting high

byte for Fan 2 FFh No Page 78

8Eh R TACH 2 Reading

High Byte Holds the tachometer reading high byte

for Fan 2 FFh No Page 79

8Fh R TACH 2 Reading

Low Byte Holds the tachometer reading low byte

for Fan 2 F8h No Page 79

Look Up Table 2 (LUT2)

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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Revision 1.78 (04-21-09) 50 SMSC EMC2106

DATASHEET

90h R/W LUT 2

Configuration S tores and controls the configuration for

LUT 2 00h No Page 80

91h R/W LUT 2 Drive 1 Stores the lowest programmed drive

setting for LUT 2 FBh LUT

Lock 2 Page 83

92h R/W LUT 2 Temp 1

Setting 1 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 1 value 7Fh

(127°C) LUT

Lock 2 Page 83

93h R/W LUT 2 Temp 2

Setting 1 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 1 value 7Fh

(127°C) LUT

Lock 2 Page 83

94h R/W LUT 2 Temp 3

Setting 1

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 1

value

7Fh

(127°C) LUT

Lock 2 Page 83

95h R/W LUT 2 Temp 4

Setting 1

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 1 value

7Fh

(127°C) LUT

Lock 2 Page 83

96h R/W LUT 2 Drive 2 Stores the second programmed drive

setting for LUT 2 E6h LUT

Lock 2 Page 83

97h R/W LUT 2 Temp 1

Setting 2 Stores the threshold level for the

External Diode 1 (or VIN1)chan nel that

is associated with the Drive 2 value 7Fh

(127°C) LUT

Lock 2 Page 83

98h R/W LUT 2 Temp 2

Setting 2 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 2 value 7Fh

(127°C) LUT

Lock 2 Page 83

99h R/W LUT 2 Temp 3

Setting 2

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 2

value

7Fh

(127°C) LUT

Lock 2 Page 83

9Ah R/W LUT 2 Temp 4

Setting 2

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 2 value

7Fh

(127°C) LUT

Lock 2 Page 83

9Bh R/W LUT 2 Drive 3 Stores the third programmed drive

setting for LUT 2 D1h LUT

Lock 2 Page 83

9Ch R/W LUT 2 Temp 1

Setting 3 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 3 value 7Fh

(127°C) LUT

Lock 2 Page 83

9Dh R/W LUT 2 Temp 2

Setting 3 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 3 value 7Fh

(127°C) LUT

Lock 2 Page 83

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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SMSC EMC2106 51 Revision 1.78 (04-21-09)

DATASHEET

9Eh R/W LUT 2 Temp 3

Setting 3

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 3

value

7Fh

(127°C) LUT

Lock 2 Page 83

9Fh R/W LUT 2 Temp 4

Setting 3

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 3 value

7Fh

(127°C) LUT

Lock 2 Page 83

A0h R/W LUT 2 Drive 4 Stores the fourth programmed drive

setting for LUT 2 BCh LUT

Lock 2 Page 83

A1h R/W LUT 2 Temp 1

Setting 4 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 4 value 7Fh

(127°C) LUT

Lock 2 Page 83

A2h R/W LUT 2 Temp 2

Setting 4 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 4 value 7Fh

(127°C) LUT

Lock 2 Page 83

A3h R/W LUT 2 Temp 3

Setting 4

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 4

value

7Fh

(127°C) LUT

Lock 2 Page 83

A4h R/W LUT 2 Temp 4

Setting 4

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 4 value

7Fh

(127°C) LUT

Lock 2 Page 83

A5h R/W LUT 2 Drive 5 Stores the fifth programmed drive

setting for LUT 2 A7h LUT

Lock 2 Page 83

A6h R/W LUT 2 Temp 1

Setting 5 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 5 value 7Fh

(127°C) LUT

Lock 2 Page 83

A7h R/W LUT 2 Temp 2

Setting 5 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 5 value 7Fh

(127°C) LUT

Lock 2 Page 83

A8h R/W LUT 2 Temp 3

Setting 5

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 5

value

7Fh

(127°C) LUT

Lock 2 Page 83

A9h R/W LUT 2 Temp 4

Setting 5

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 5 value

7Fh

(127°C) LUT

Lock 2 Page 83

AAh R/W LUT 2 Drive 6 Stores the sixth programmed drive

setting for LUT 2 92h LUT

Lock 2 Page 83

ABh R/W LUT 2 Temp 1

Setting 6 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 6 value 7Fh

(127°C) LUT

Lock 2 Page 83

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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DATASHEET

ACh R/W LUT 2 Temp 2

Setting 6 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 6 value 7Fh

(127°C) LUT

Lock 2 Page 83

ADh R/W LUT 2 Temp 3

Setting 6

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 6

value

7Fh

(127°C) LUT

Lock 2 Page 83

AEh R/W LUT 2 Temp 4

Setting 6

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 6 value

7Fh

(127°C) LUT

Lock 2 Page 83

AFh R/W LUT 2 Drive 7 Stores the seventh programmed drive

setting for LUT 2 92h LUT

Lock 2 Page 83

B0h R/W LUT 2 Temp 1

Setting 6 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 7 value 7Fh

(127°C) LUT

Lock 2 Page 83

B1h R/W LUT 2 Temp 2

Setting 6 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 7 value 7Fh

(127°C) LUT

Lock 2 Page 83

B2h R/W LUT 2 Temp 3

Setting 6

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 7

value

7Fh

(127°C) LUT

Lock 2 Page 83

B3h R/W LUT 2 Temp 4

Setting 6

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 7 value

7Fh

(127°C) LUT

Lock 2 Page 83

B4h R/W LUT 2 Drive 8 Stores the highest programmed drive

setting for LUT 2 92h LUT

Lock 2 Page 83

B5h R/W LUT 2 Temp 1

Setting 8 Stores the threshold level for the

External Diode 1 (or VIN1) channel that

is associated with the Drive 8 value 7Fh

(127°C) LUT

Lock 2 Page 83

B6h R/W LUT 2 Temp 2

Setting 8 Stores the threshold level for the

External Diode 2 (or VIN2) channel that

is associated with the Drive 8 value 7Fh

(127°C) LUT

Lock 2 Page 83

B7h R/W LUT 2 Temp 3

Setting 8

Stores the threshold level for the

External Diode 3 channel (or VIN3 or

TRIP_SET voltage or Pushed Temp 3

temp) that is associated with the Drive 8

value

7Fh

(127°C) LUT

Lock 2 Page 83

B8h R/W LUT 2 Temp 4

Setting 8

Stores the threshold level for the

Internal Diode channel (or Pushed

Temp 4 temp) that is associated with the

Drive 8 value

7Fh

(127°C) LUT

Lock 2 Page 83

B9h R/W LUT 2 Temp

Hysteresis Stores the hysteresis that is shared for

all temperature inputs 0Ah

(10°C) LUT

Lock 2 Page 83

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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DATASHEET

During Power-On-Reset (POR), the default val ues are stored in the registers. A POR is initiated when

power is first applied to the part and the voltage on the VDD supply surpasses the POR level as

specified in the electrical characteristics. Any reads to undefined registers will return 00h. Writes to

undefined registers will not have an effect.

6.1.1 Lock Entries

The Lock Column describes the locking mechanism, if any, used for individual registers. All SWL

registers are Software Locked and therefore made read-only when the LOCK bit is set.

GPIO Registers

E0h R/W Muxed Pin

Configuration

muxed with PWMs or GPIOs 01h No Page 85

E1h R/W GPIO Direction

- 6 00h No Page 86

E2h R/W GPIO Output

Configuration

E3h R GPIO Input

E4h R/W GPIO Output

E5h R/W GPIO Interrupt

Enable Register Enabled Interrupts for GPIOs 1 - 6 00h No Page 87

E6h R GPIO Status Indicates change of state for inputs on

GPIOs 1 - 6 00h No Page 88

Lock Register

EF R/W Software Lock Locks all SWL registers 00h SWL Page 88

Revision Registers

FCh R Product Features Stores information about which pin

controlled product features are set 00h No Page 89

FDh R Product ID Stores the unique Product ID 1Eh No Page 89

FEh R Manufacturer ID Stores the Manufacturer ID 5Dh No Page 89

FFh R Revision Revision 02h No Page 90

Table 6.1 EMC2106 Register Set (continued)

ADDR R/W REGISTER

NAME FUNCTION DEFAULT

VALUE LOCK PAGE

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DATASHEET

6.2 Temperature Data Registers

The temperature measurement range is from -64°C to +128°C. The data format is a signed two’s

complement number as shown in Table 6.3.

APPLICATION NOTE: When each of the External Diode 1, External Diode 2, or External Diode 3 channels are

configured as a voltage input, the voltage data will be stored in the corresponding data

determined by adding the ap propriately set bits together. This data will be compared against

the limits normally (see Section 6.22).

Table 6.2 Temperature Data Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

00h R Internal Diode

High Byte Sign 64 32 16 8 4 2 1 00h

01h R Internal Diode

Low Byte 0.5 0.25 0.125 - - - - - 00h

02h R

External

Diode 1 High

Byte Sign 64 32 16 8 4 2 1 00h

VIN1 400 200 100 50 25 13.5 6.25 3.125 00h

03h R External

Diode 1 Low

Byte 0.5 0.25 0.125 - - - - - 00h

04h R

External

Diode 2 High

Byte Sign 64 32 16 8 4 2 1 00h

VIN2 400 200 100 50 25 13.5 6.25 3.125 00h

05h R External

Diode 2 Low

Byte 0.5 0.25 0.125 - - - - - 00h

06h R

External

Diode 3 High

Byte Sign 64 32 16 8 4 2 1 00h

VIN3 400 200 100 50 25 13.5 6.25 3.125 00h

07h R External

Diode 3 Low

Byte 0.5 0.25 0.125 - - - - - 00h

08h R External

Diode 4 High

Byte Sign 64 32 16 8 4 2 1 00h

09h R External

Diode 4 Low

Byte 0.5 0.25 0.125 - - - - - 00h

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DATASHEET

6.3 Critical/Thermal Shutdown Temperature Registers

The Critical/Thermal Shutdown Temperature Register is a read-only register that stores the Voltage

Programmable Threshold temperature used in the Thermal / Critical Shutdown circuitry. The contents

of the register reflect the calculated temperature based on the TRIP_SET voltage. This register is

updated at the end of every monitoring cycle based on the current value of the TRIP_SET voltage.

The data format is shown in Table 6.5.

Table 6.3 Temperature Data Format

TEMPERATURE (°C) BINARY HEX (AS READ BY

REGISTERS)

Diode Fault 1000_0000_000b 80_00h

-63.875 1100_0000_001b C0_20h

-63 1100_0001_000b C1_00h

-1 1111_1111_000b FF_00h

-0.125 1111_1111_111b FF_E0h

0 0000_0000_000b 00_00h

0.125 0000_0000_001b 00_20h

1 0000_0001_000b 01_00h

63 0011_1111_000b 3F_00h

64 0100_0000_000b 40_00h

65 0100_0001_000b 41_00h

127 0111_1111_000b 7F_00h

127.875 0111_1111_111b 7F_E0h

Table 6.4 Critical/Thermal Shutdown Temperature Registers

ADDRR/WREGISTER B7B6B5B4B3B2B1B0DEFAULT

0Ah R Critical/Thermal

Shutdown

Temperature 128 64 32 16 8 4 2 1 7Fh

(+127°C)

Table 6.5 Critical / Thermal Shutdown Data Format

TEMPERATURE (°C) BINARY HEX

0 0000_0000b 00h

1 0000_0001b 01h

63 0011_1111b 3Fh

64 0100_0000b 40h

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DATASHEET

6.4 Pushed Temperature Registers

The Pushed Temperature Registers store user programmed temperature values that can be used by

the look-up table to update the fan control algorithm. Data written in these registers is not compared

against any limits and must match the data format shown in Table 6.3.

6.5 Voltage Registers

The Voltage Registers hold the data read from the TRIP_SET voltage input. The TRIP_SET voltage is

stored whether the TRIP_SET is u sed to set the The rmal / C riti cal Shutdown temp erature or configu red

to act as the VIN4 input.

Each bit weight represents mV of reso lution so that the final voltage can be determi ned by adding the

appropriately set bits together.

65 0100_0001b 41h

127 0111_1111b 7Fh

130 1000_0010b 82h

150 1001_0110b 96h

Tab le 6.6 Pushed Temperature Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

0Ch R/W Pushed

Temperature 1 Sign 64 32 16 8 4 2 1 00h

0Dh R/W Pushed

Temperature 2 Sign 64 32 16 8 4 2 1 00h

0Eh R/W Pushed

Temperature 3 Sign 64 32 16 8 4 2 1 00h

0Fh R/W Pushed

Temperature 4 Sign 64 32 16 8 4 2 1 00h

Table 6.7 TripSet Voltage Register

ADDRR/W REGISTER B7B6B5B4B3B2B1B0DEFAULT

10h R TRIP_SET

Voltage / VIN4

Voltage 400 200 100 50 25 13.5 6.25 3.125 FFh

Tabl e 6.5 Critical / Thermal Shutdown Data Format (continued)

TEMPERATURE (°C) BINARY HEX

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DATASHEET

6.6 Beta Configuration Registers

The Beta Configuration Registers control advanced temperature measurement features for each

External Diode channel. The Beta Configuration Registers are software locked. The External Diode 1

Beta Configuration Register Is hardware locked if the SHDN_SEL pin is not set to disable the Critical

/ Thermal Shutdown functionality (see Table 6.1).

Bit 4 - AUTO - Enables the Automatic Beta detection algorithm.

‘0’ - The Automatic Beta detection algorithm is disabled. The BETAx[3:0] bit settings will be used

to control the beta compensation circuitry.

‘1’ (default) - The Automatic Beta detection algorithm is enabled. The circuitry will automatically

detect the transistor type and beta values and configure the BETAx[3:0] bits for optimal

performance.

Bits 3 - 0 - BETAx[3:0] - hold a value that corresponds to a range of betas that the Beta Compensation

circuitry can compensate for. These four bits will always show the current beta setting used by the

circuitry. If the AUTO bit is set (default), then these bits may updated by the device with every

temperature conversion. If the AUTO bit is not set, then the value of these bits is used to drive the

beta compensation circuitry. In this case, these bits should be set with a value corresponding to the

lowest expected value of beta for the PNP transistor being used as a temperature sensing device.

See Table 6.9 for supported beta ranges. A value of 1111b indicates that the beta compensation

circuitry is disabled. In this condition, the diode channels will function with default current levels and

will not automatically adjust for beta variation. This mode is used when measuring a discrete 2N3904

transistor or AMD thermal diode.

All of the Beta Configuration Registers are Software Locked.

Table 6.8 Beta Configuration Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

14h R/W External Diode 1

Beta

Configuration - - - AUTO BETA1[3:0] 10h

15h R/W External Diode 2

Beta

Configuration - - - AUTO BETA2[3:0] 10h

16h R/W External Diode 3

Beta

Configuration - - - AUTO BETA3[3:0] 10h

Table 6.9 Beta Compensation Look Up Table

AUTO

BETAX[3:0]

MINIMUM BETA3210

00000 0.050

00001 0.066

00010 0.087

00011 0.114

00100 0.150

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DATASHEET

6.7 REC Configuration Register

The REC Configuration Register determines whether Resistance Error Correction is used for each

external diode channel. The REC Configuration Register is software locked.

Bit 2 - REC3 - Controls the Resistive Error Correction functionality of External Diode 3 and External

Diode 4 (if APD is enabled, see Section 6.9)

‘0’ - the REC functionality for External Diode 3 is disabled

‘1’ (default) - the REC functionality for External Diode 3 is enabled.

Bit 1 - REC2 - Controls the Resistive Error Correction functionality of External Diode 2.

‘0’ - the REC functionality for External Diode 2 is disabled

‘1’ (default) - the REC functionality for External Diode 2 is enabled.

Bit 0 - REC1 - Controls the Resistive Error Correction functionality of External Diode 1. This bit is

locked if the SHDN_SEL pin is not pulled to VDD (see Table 6.1).

‘0’ - the REC functionality for External Diode 1 is disabled

‘1’ (default) - the REC functionality for External Diode 1 is enabled.

00101 0.197

00110 0.260

00111 0.342

01000 0.449

01001 0.591

01010 0.778

01011 1.024

01100 1.348

01101 1.773

01110 2.333

01111 Disabled

1 X X X X Automatically detected

Table 6.10 REC Configuration Register

ADDRR/W REGISTER B7B6B5B4B3B2B1B0DEFAULT

17h R/W REC

Configuration - - - - - REC3 REC2 REC1 07h

Table 6.9 Beta Compensation Look Up Table (continued)

AUTO

BETAX[3:0]

MINIMUM BETA3210

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SMSC EMC2106 59 Revision 1.78 (04-21-09)

DATASHEET

6.8 Critical Temperature Limit Registers

The Critical Temperature Limit Regi sters store the Critical Te mperature Limit. At power up, none of the

respective channels are linked to the SYS_SHDN pin or the Hardware set Thermal/Critical Shutdown

circuitry.

Whenever one of the regi sters is updated, two things occur. First, the register is locked so that it cannot

be updated again without a power on reset. Second, the respective temperature channel is linked to

the SYS_SHDN pin and the Hardware set Thermal/Critical Shutdown Circuitry. At this point, if the

measured temperature channel exceeds the Critical limit, the SYS_SHDN pin will be asserted, the

appropriate bit set in the Tcrit Status Register, and the TCRIT bit in the Interrupt Status Register will

be set.

6.9 Configuration Register

The Configuration Register controls the basic functionality of the EMC2106. The bits are described

below. The Configuration Register is software locked.

Bit 7 - MASK - Blocks the ALERT# pin from being asserted.

‘0’ (default) - The ALERT# pin is unmasked. If any bit in either status register is set, the ALERT#

pins will be asserted (unless individually masked via the Mask Register)

‘1’ - The ALERT# pin is masked and will not be asserted.

Bit 4 - SYS4 - Enables the high temperature limit for the External Diode 4 channel to trigger the Cr itical

/ Thermal Shutdown circuitry (see Section 6.1). This bit is ignored if th e DP3 / DN3 pins are configured

to measure a voltage input. In this case, the External Diode 4 channel is disabled and not compared

against any limits.

‘0’ (default) - the External Diode 4 channel high limit will not be linked to the SYS_SHDN# pin. If

the temperature exceeds the limit, the ALERT# pin will be asserted normally.

‘1’ - the External Diode 4 channel high limit will be linked to the SYS_SHDN# pin. If the temperature

exceeds the limit then the SYS_SHDN# pin will be asserted. The SYS_SHD N# pin w ill be release d

Table 6.11 Limit Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

19h R/W

once External Diode

1 Tcrit Limit Sign 64 32 16 8 4 2 1 64h

(+100°C)

1Ah R/W

once External Diode

2 Tcrit Limit Sign 64 32 16 8 4 2 1 64h

(+100°C)

1Bh R/W

once External Diode

3 Tcrit Limit Sign 64 32 16 8 4 2 1 64h

(+100°C)

1Ch R/W

once External Diode

4 Tcrit Limit Sign 64 32 16 8 4 2 1 64h

(+100°C)

1Dh R/W

once Internal Diode

Tcrit Limit Sign 64 32 16 8 4 2 1 64h

(+100°C)

Table 6.12 Configuration Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

20h R/W Configuration MASK - - SYS4 SYS3 SYS2 SYS1 APD 00h

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when the temperature drops below the high limit. The ALERT# pin will be asserted and released

normally.

Bit 3 - SYS3 - Enables the high temperature limit for the External Diode 3 channel to trigger the Cr itical

/ Thermal Shutdown circuitry (see Section 6.1).

Bit 2 - SYS2 - Enables the high temperature limit for the External Diode 2 channel to trigger the Cr itical

/ Thermal Shutdown circuitry (see Section 6.1).

Bit 1 - SYS1 - Enables the high temperature limit for the External Diode 1 channel to trigger the Cr itical

/ Thermal Shutdown circuitry (see Section 6.1).

Bit 0 - APD - This bit enables the Anti-parallel diode functionality on the External Diode 3 pins (DP3

and DN3).

‘0’ (default) - The Anti-parallel diode functionality is disabled. The Exte rnal Diode 3 cha nnel can be

configured for any type of diode

‘1’ - The Anti-parallel diode functionality is en abled. Both the External Diode 3 and 4 channels are

configured to support a diode or diode connected transistor (such as a 2N3904).

APPLICATION NOTE: When the APD diode is enabled, there will be a delay of a full temperature update before

any comparisons and functionality associated with the External Diode 4 channel will be

implemented. This includes the SYS4 bit operation, limit comparisons, and look up table

comparisons.

6.10 Configuration 2 Register

The Configuration 2 Register controls conversion rate of the temperature monitoring as well as the

fault queue. This register is software locked.

Bit 6 - DIS_DYN - Disables the Dynamic Averaging Feature.

‘0’ (default) - The Dynamic Averaging functi on is enabled. The conversion time for all temperature

channels is scaled based on the chosen conversion rate to maximize accuracy and immunity to

random temperature measurement variation.

‘1’ - The Dynamic Averaging function is disable d. The conversio n time for all temperature ch annels

is fixed regardless of the chosen conversion rate.

Bit 5 - DIS_TO - Disables the SMBus time out function for the SMBus client (if enabled).

‘0’ (default) - The SMBus time out function is enabled.

‘1’ - The SMBus time out function is disabled allowing the device to be fully I2C compliant.

Bit 4 - DIS_AVG - Disables digital averaging of the External Diode 1 channel.

‘0’ (default) - The External Diode 1 channel has digital averaging enabled. The temperature data

is the average of the previous four measurements.

‘1’ - The External Diode 1 channel has digital averagin g disabled. The temperature da ta is the last

measured data.

Bits 3-2 - QUEUE[1:0] - Determines the number of consecutive out of limit conditions that are

necessary to trigger an interrupt. Each measurement channel has a separate fault queue associated

with the high limit, low limit, and diode fault condition except the internal diode.

Table 6.13 Configuration 2 Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

21h R/W Config 2 - DIS_

DYN DIS_

TO DIS_

AVG QUEUE[1:0] CONV[1:0] 0Eh

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The Critical / Thermal Shutdown temperature has a separate fault queue that applies to the selected

hardware shutdown channel (see Section 6.1.1) when compared against the threshold set by the

TRIP_SET pin.

APPLICATION NOTE: If the fault queue for any channel is currently active (i.e. an out of limit condition has been

detected and caused the fault queue to increment) then changing the settings will not take

effect until the fault queue is zeroed. This occurs by the ALERT# pin asserting or the out of

limit condition being removed.

Bit 1 - 0 - CONV[1:0] - determi nes the conversion rate of the temperature monitoring. This conversion

rate does not affect the fan driver. The supply current from VDD_3V is nominally dependent upon the

conversion rate and the average current will increase as the conversion rate increases.

6.11 Configuration 3 Register

The Configuration 3 Register controls the fou r voltage input channels. This register is software locked.

Bit 6 - VIN4_INV - Determines whether the VIN4 channel data is inverted.

‘0’ (default) - The VIN4 channel data is not inverted.

Table 6.14 Fault Queue

QUEUE[1:0]

NUMBER OF CONSECUTIVE OUT OF LIMIT CONDITIONS 10

0 0 1 (disabled)

01 2

10 3

1 1 4 (default)

Table 6.15 Conversio n Rate

CONV[1:0]

CONVERSION RATE

TEMPERATURE OVER SAMPLING

FROM 11 BITS

1 0 DYN_DIS = ‘0’ DYN_DIS = ‘1’

0 0 1 / sec x8 x1

0 1 2 / sec x4 x1

1 0 4 / sec (default) x2 x1

1 1 Continuous x1 x1

Table 6.16 Configuration 3 Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

22h R/W Config 3 - VIN4_I

NV VIN3

_EN VIN3

_INV VIN2

_EN VIN2

_INV VIN1

_EN VIN1

_INV 00h

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‘1’ - The VIN4 channel data is inverted. The data presented to th e reading registers and compared

against the limits is determined as FFh - the measured input voltage.

APPLICATION NOTE: If the TRIP_SET / VIN4 pin is configured to be used to set the Critical / Thermal Shutdown

temperature associated with the External Diode 1 channel, then this bit cannot be set.

Bit 5 - VIN3_EN - Enables the voltage mode on the External Diode 3 channel.

‘0’ (default) - The External Diode 3 channel operates as a diode channel.

‘1’ - The External Diode 3 channel operates as a voltage input. The DP3 / DN4 / VREF_T3 pin

acts as a reference output voltage and the DN3 / DP4 /. VIN3 pin acts as a voltage input. This

overrides the APD bit in the Configuration 1 Register (20h).

Bit 4 - VIN3_INV - Determines whether the VIN3 channel data is inverted.

Bit 3 - VIN2_EN - Enables the voltage mode on the External Diode 2 channel.

Bit 2 - VIN2_INV - Determines whether the VIN2 channel data is inverted.

Bit 1 - VIN1_EN - Enables the voltage mode on the External Diode 1 channel.

Bit 0 - VIN1_INV - Determines whether the VIN1 channel data is inverted.

APPLICATION NOTE: If the TRIP_SET / VIN4 pin is configured to be used to set the Critical / Thermal Shutdown

temperature associated with the External Diode 1 channel, then neither Bit 1 nor Bit 0 can

be set.

6.12 Interrupt Status Register

The Interrupt Status Register reports the operating condition of the EMC2106. If any of the bits are set

to a logic ‘1’ (other than TSD an d HWS) then the ALERT# pin will be asserted low if the corresponding

channel is enabled. Reading from the status register clears all status bits if the error conditions is

removed. If there are no set status bits, then the ALERT# pin will be released.

The bits that cause the ALERT# pin to be asserted can be masked based on the channel they are

associated with unless stated otherwise.

Bit 7 - EEPROM - This bit is set to ‘1’ if the EEPROM loader circuitry detects an error when writing

data from the EEPROM. This bit is cleared when the register is read. This bit is not masked except

via the MASK bit.

Bit 6 - TSD - This bit is set to ‘1’ if the internal Thermal Sh utdown (TSD) circuit trips indicating that the

die temperature has exceeded its threshold. When this bit is set, it will not cause the ALERT# pin to

be asserted however will coincide with the SYS_SHDN# pin being asserted. This bit is cleared when

the register is read and the error condition has been removed.

Bit 5 - TCRIT - This bit is set to ‘1’ whenever the any bit in the Tcrit Status Register is set. This bit is

automatically cleared when the Tcrit Status Register is cleared.

Bit 4 - GPIO - This bit is set to ‘1’ if any of the bits in the GPIO Status Registers are set.

Bit 3 - FAN - This bit is set to ‘1’ if any bit in the Fan Status Register is set. This bit is automatically

cleared when the Fan Status Register is read and the bits are cleared.

Table 6.17 Interrupt Status Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

23h R-C Interrupt

Status

EEPR

OM TSD TCRIT GPIO FAN HIGH LOW FAULT 00h

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Bit 2 - HIGH - This bit is set to ‘1’ if any bit in the High Status Register is set. This bit is automatically

cleared when the High Status Register is read and the bits are cleared.

Bit 1- LOW - This bit is set to ‘1’ if any bit in the Low Status Register is set. This bit is automatically

cleared when the Low Status Register is read and the bits are cleared.

Bit 0 - FAULT - This bit is set to ‘1’ if any bit in the Diode Faul t Register is set. This bit is automatica lly

cleared when the Diode Fault Register is read and the bits are cleared.

6.13 Error Status Registers

The Error Status Registers report the specific error condition for all measure ment chann els with limits.

If any bit is set in the High, Low, or Diode Fault Status register, the corresponding High, Low, or Fault

bit is set in the Interrupt Status Register.

Reading the Interrupt Status Register does not clear the Error Status bit. Reading from any Error Status

Status Registers will have no affect.

If any of the External Diode 1, External Diode 2, or External Diode 3 channels are configured as a

voltage input, then the corresponding tempera ture cha nne l status bit will b e set if the measured vol tage

exceeds the high limit or falls below the low limit. In this condition, a diode fault will be ignored.

APPLICATION NOTE: If any of the External Diode 1, 2, or 3 channels are configured as a voltage input and

thermistor or other voltage source is used on the corresponding pins at device power up,

then the corresponding diode fault status bits will be set. The status bits should be cleared

prior to enabling the interrupts to avoid erroneous alert conditions.

6.13.1 Tcrit Status Register

The Tcrit Status Register stores the event that caused the SYS_SHDN# pin to be asserted. Each of

the temperature channels must be associated with the SYS_SHDN# pin before they can be set (see

Section 6.8). Once the SYS_SHDN# pin is asserted, it will be released when the temperature drops

below the threshold level however the individual status bit will not be cleared until read.

Bit 7 - HWS - This bit is set if the hardware set temperature channel meets or exceeds the temperature

threshold determined by the TRIP_SET voltage.

Table 6.18 Error Status Regi ste r

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

1Fh R-C Tcrit Status HWS - - EXT4_

CRIT EXT3_

CRIT EXT2_

CRIT EXT1

_CRIT INT_

CRIT 00h

24h R-C High Status - - VOLT

4_HI EXT4_

HI EXT3_

HI EXT2_

HI EXT1

_HI INT_

HI 00h

25h R-C Low Status - - VOLT

4_LO EXT4_

LO EXT3_

LO EXT2_

LO EXT1

_LO INT_L

O00h

26h R-C Diode Fault - - - EXT4_

FLT EXT3_

FLT EXT2_

FLT EXT1

_FLT -00h

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6.14 Fan Status Register

The Fan Status Register contains the status bits associated with each fan driver. This register is

cleared when read if the error condition has been removed.

Bit 7 - WATCH - This bit is asserted ‘1’ if the host has not programmed the fan driver(s) within four (4)

seconds after power up.

Bit 6 - DRIVE_FAIL2 - Indicates that the RPM based Fan Speed Control Algorithm cannot drive Fan

2 to the desired target setting at maximum drive. This bit can be masked from asserting the ALERT#

pin.

‘0’ - The RPM based Fan Speed Control Algorithm can drive Fan 2 to the desired target setting.

‘1’ - The RPM based Fan Speed Control Algorithm cann ot drive Fan 2 to the desired target setting

at maximum drive.

Bit 6 - DRIVE_FAIL1 - Indicates that the RPM based Fan Speed Control Algorithm cannot drive Fan

1 to the desired target setting at maximum drive. This bit can be masked from asserting the ALERT#

pin.

‘0’ - The RPM based Fan Speed Control Algorithm can drive Fan 1 to the desired target setting.

‘1’ - The RPM based Fan Speed Control Algorithm cann ot drive Fan 1 to the desired target setting

at maximum drive.

Bit 5 - FAN_SHORT - This bit is asserted ‘1’ if the High Side Fan Driver detects an over current

condition that lasts for longer than 2 seconds.

Bit 3 - FAN_SPIN 2- This bit is asserted ‘1’ if the Spin up Routine for Fan 2 cannot detect a valid

tachometer reading within its maximum time window. This bit can be masked from asserting the

ALERT# pin.

Bit 2 - FAN_STALL 2 - This bit is asserted ‘1’ if the tachometer measurement on Fan 2 detects a stalled

fan. This bit can be masked from asserting the ALERT# pin.

Bit 1- FAN_SPIN1- This bit is asserted ‘1’ if the Spin up Routine for Fan 1 cannot detect a valid

tachometer reading within its maximum time window. This bit can be masked from asserting the

ALERT# pin.

Bit 0 - FAN_STALL1 - Thi s bit is asserted ‘1’ if the tachometer measurement on Fan 1 de tects a stalled

fan. This bit can be masked from asserting the ALERT# pin.

6.15 Interrupt Enable Register

Table 6.19 Fan Status Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

27h R-C Fan Status

_FAIL2 DRIVE

_FAIL1 FA N_

SHORT FAN_

SPIN2 FAN_

STALL2 FAN_

SPIN1 FAN_

STALL1 00h

Table 6.20 Interrupt Enable Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

28 R/W Interrupt

Enable --

VOLT4_I

NT_EN EXT4_I

NT_EN EXT3_I

NT_EN EXT2_I

NT_EN EXT1_I

NT_EN INT_IN

T_EN 00h

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The Interrupt Enable Register controls the masking for each temperature channel. When a channel is

masked, it will not cause the ALERT# pin to be asserted when an error condition is detected.

Bit 5 - VOLT4_INT_EN - Allows the Voltage Input 4 channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will be not be asserted for any error condition associated with

Voltage Channel 4 (TRIP_SET / VIN4).

‘1’ - The ALERT# pin will be asserted for an error condition associated with Voltage Channel 4.

Bit 4 - EXT4_INT_EN - Allows the External Diode 4 channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will be not be asserted for any error condition associated with

External Diode 4.

‘1’ - The ALERT# pin will be asserted for an error condition associated with External Diode 4.

Bit 3 - EXT3_INT_EN - Allows the External Diode 3 or VIN3 channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will not be asserted for any error condition associated with External

Diode 3 or VIN3 channels.

‘1’ - The ALERT# pin will be asserted for an error condition associated with External Diode 3 or

VIN3 channels.

Bit 2 - EXT2_INT_EN - Allows the External Diode 2 or VIN2 channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will not be asserted for any error condition associated with External

Diode 2 or VIN2 channels.

‘1’ - The ALERT# pin will be asserted for an error condition associated with External Diode 2 or

VIN2 channels.

Bit 1 - EXT1_INT_EN - Allows the External Diode 1 or VIN1 channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will not be asserted for any error condition associated with External

Diode 1 or VIN1 channels.

‘1’ - The ALERT# pin will be asserted for an error condition associated with External Diode 1 or

VIN1 channels.

Bit 0 - INT_INT_EN - Allows the Internal Diode channel to assert the ALERT# pin.

‘0’ (default) - The ALERT# pin will not be asserted for any error condition associated with the

Internal Diode.

‘1’ - The ALERT# pin will be asserted for an error condition associated with the Internal Diode.

6.16 Fan Interrupt Enable Register

The Fan Interrupt Enable controls the masking for each Fan channel. When a channel is enabled, it

will cause the ALERT# pin to be asserted when an error condition is detected.

Bit 3 - SPIN_INT_EN2 - Allows the FAN_SPIN 2 bit to assert the ALERT# pin.

‘0’ (default) - the FAN_SPIN 2 bit will not assert the ALERT# pin though will still up date the Status

‘1’ - the FAN_SPIN2 bit will assert the ALERT# pin.

Table 6.21 Fan Interrupt Enable Register

ADDRR/WREGISTERB7B6B5B4 B3 B2 B1B0DEFAULT

29h R/W Fan

Interrupt

Enable ----

SPIN_

INT_EN2 STALL_

INT_EN2 SPIN_

INT_EN

STALL_

INT_EN

100h

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Bit 2 - STALL_INT_EN2 - Allows the FAN_STALL2 bit or DRIVE_FAIL2 bit to assert the ALERT# pin.

‘0’ (default) - the FAN_STALL2 bit or DRIVE_FAIL2 bi t will not assert the ALERT# pin though it will

still update the Status Register normally.

‘1’ - the FAN_STALL 2 or DRIVE_FAIL2 bits will assert the ALERT# pin if set.

Bit 1 - SPIN_INT_EN1 - Allows the FAN_SPIN1 bit to assert the ALERT# pin.

‘0’ (default) - the FAN_SPIN1 bit will not assert t he ALERT# pin though it will still update the Status

‘1’ - the FAN_SPIN1 bit will assert the ALERT# pin.

Bit 0 - STALL_INT_EN1 - Allows the FAN_STALL1 bit or DRIVE_FAIL1 bit to assert the ALERT# pin.

‘0’ (default) - the FAN_STALL1 bit or DRIVE_FAIL1 bit will not assert the ALERT# pin though will

still update the Status Register normally.

‘1’ - the FAN_STALL1 or DRIVE_FAIL1 bit will assert the ALERT# pin if set.

6.17 PWM Configuration Register

The PWM Config Register controls the output type and polarity of all PWM outputs.

Bit 3 - POLARITY4 - Determines the polarity of PWM4 (if enabled).

‘0’ (default) - the Polarity o f the PWM driver is normal. A drive setting of 00h will cause the ou tput

to be set at 0% duty cycle and a drive setting of FFh will cause the output to be set at 100% duty

cycle.

‘1’ - The Polarity of the PWM driver is inverted. A drive setting of 00h will cause the output to be

set at 100% duty cycle and a drive setting of FFh will cause the output to be set at 0% duty cycle.

Bit 2 - POLARITY3 - Determines the polarity of PWM3 (if enabled).

Bit 1 - POLARITY2 - Determines the polarity of PWM2 (if enabled).

Bit 0 - POLARITY1 - Determines the polarity of PWM1 (if enabled).

6.18 PWM Base Frequency Register

The PWM Base Frequency Registe r determines the base frequency that is used with the PWM Divide

the PWM Divide Register.

Table 6.22 PWM Configuration Register

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

2Ah R/W PWM

Config ----

POLA

RITY4 POLA

RITY3 POLA

RITY2 POLA

RITY1 00h

Table 6.23 PWM Base Frequen cy Register

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

2Bh R/W PWM Base

Frequency PWM_

BASE

4_1

PWM_

BASE

4_0

PWM_

BASE

3_1

PWM_

BASE

3_0

PWM_

BASE

2_1

PWM_

BASE

2_0

PWM_

BASE

1_1

PWM_

BASE

1_0 FFh

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Bits 7-6 - PWM_BASE4[1:0] - Determines the base frequency of the PWM4 driver (GPIO3 / PWM4

pin).

Bits 5-4 - PWM_BASE3[1:0] - Determines the base frequency of the PWM3 driver (GPIO2 / PWM3

pin).

Bits 3-2 - PWM_BASE2[1:0] - Determines the base frequency of the PWM2 driver (PWM2 / GPIO4

pin).

Bits 1-0 - PWM_BASE1[1:0] - Determines the base frequency of the PWM1 driver (PWM1).

6.19 PWM 3 and 4 Divide Registers

The PWM 3 and PWM 4 Divide Registers determine the final frequency of the PWM 3 and PWM 4

drivers respectively. Each driver base frequency is divided by the value of the PWM Divide Register

to determine the final frequency. The duty cycle settings are not affected by these settings, only the

final frequency of the PWM driver. A value of 00h will be decoded as 01h.

6.20 PWM 3 Setting Register

The PWM 3 Input Register controls the output of the GPIO2 / PWM3 pin when it is configured as a

PWM output. The input code represents the number of counts out of a total of 255 that the output will

be high for.

Table 6.24 PWM_BASEx[1:0] Bit Decode

PWM_BASEX[1:0]

BASE FREQUENCY10

0 0 26.00kHz

0 1 19.531kHz

1 0 4,882Hz

1 1 2,441Hz (default)

Table 6.25 PWM Divide Registers

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

2Ch R/W PWM 3

Divide 128643216 8 4 2 1 50h

(80)

2Fh R/W PWM 4

Divide 128643216 8 4 2 1 50h

(80)

Table 6.26 PWM 3 Setting Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

2Dh R/W PWM 3

Setting 128643216 8 4 2 1 00h

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The setting operates independen tly of the PWM polarit y A value of FFh co rresponds to fully o n (default

100% duty cycle) while a value of 00h corresponds to a fully off (default 0% duty cycle).

6.21 PWM 4 Setting Register

The PWM 4 Input Register controls the output of the GPIO3 / PWM4 pin when it is configured as a

PWM output. The input code represents the number of counts out of a total of 255 that the output will

be high for.

The setting operates independen tly of the PWM polarit y A value of FFh co rresponds to fully o n (default

100% duty cycle) while a value of 00h corresponds to a fully off (default 0% duty cycle).

6.22 Limit Registers

Table 6.27 PWM 4 Setting Register

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

2Eh R/W PWM 4

Setting 128643216 8 4 2 1 00h

Table 6.28 Limit Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

30h R/W External Diode

1 High Limit Sign 64 32 16 8 4 2 1 55h

(+85°C)

31h R/W External Diode

2 High Limit Sign 64 32 16 8 4 2 1 55h

(+85°C)

32h R/W External Diode

3 High Limit Sign 64 32 16 8 4 2 1 55h

(+85°C)

33h R/W External Diode

4 High Limit Sign 64 32 16 8 4 2 1 55h

(+85°C)

34h R/W Internal Diode

High Limit Sign 64 32 16 8 4 2 1 55h

(+85°C)

35h R/W VIN4 High

Limit 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 FFh

(0.8V)

38h R/W External Diode

1 Low Limit Sign 64 32 16 8 4 2 1 00h

(0°C)

39h R/W External Diode

2 Low Limit Sign 64 32 16 8 4 2 1 00h

(0°C)

3Ah R/W External Diode

3 Low Limit Sign 64 32 16 8 4 2 1 00h

(0°C)

3Bh R/W External Diode

4 Low Limit Sign 64 32 16 8 4 2 1 00h

(0°C)

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The EMC2106 contains high limits for all temperature channels and voltage channels. If any

measurement meets or exceeds the high limit then the appropriate status bit is set and the ALERT#

pin are asserted (if enabled).

APPLICATION NOTE: If any of the External Diode 1, External Diode 2, External Diode 3 is configured to operate

as a voltage input, then the corresponding temperature high and low limit registers are

compared against the measured voltage. The data format is the same as the measured

voltage and these registers should be updated accordingly.

Additionally, the EMC2106 contains low li mits for all temperature channels. If the temperature channel

drops below the low limit, then the appropriate status bit is set and the ALERT# pin are asserted (if

enabled).

All Limit Registers are Software Locked.

6.23 Fan Setting Registers

The Fan 1 Setting Register always displays the current setting of the Fan 1 Driver. Likewise, the Fan

2 Setting Register always disp lays the current setting of the Fan 2 driver. Reading from either register

will report the current fan speed setting of the appr opriate fan driver reg ardless of the ope rating mode.

Therefore it is possible that reading from this register will not report data that was previously written

into this register.

While the RPM based Fan Speed Control Algorithm or the Look Up Table are active (or both), then

the register is read only. Writing to the register will have no affect and the data will not be stored.

If both the RPM based Fan Control Algorithm and the Look Up Table are disabled, then the register

will be set with th e previous value that was used. T he register is read / wr ite and writing to this register

will affect the fan speed.

If the Fan 2 fan driver is disabled and the DAC2 / PWM2 / GPIO2 and TACH2 / GPIO1 pins are used

as GPIOs, then the Fan 2 Setting Register will read 00h.

The contents of the register represent the we ighting of each bit in determining the final output voltage.

The output drive for a PWM output is given by Equation [2]. Th e output drive for the Linear DAC driver

is given by Equation [3].T he output drive for the High Side Fan Driver output is give n by Equation [4].

3Ch R/W Internal Diode

Low Limit Sign 64 32 16 8 4 2 1 00h

(0°C)

3Dh R/W VIN 4 Low

Limit 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 00h

(0V)

Tabl e 6.29 Fan Driver Setting Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

40h R/W Fan 1 Setting 128 64 32 16 8 4 2 1 00h

80h R/W Fan 2 Setting 128 64 32 16 8 4 2 1 00h

Table 6.28 Limit Registers (continued)

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

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6.24 PWM 1 and 2 Divide Registers

The PWM 1 and 2 Divide Registers determine the final frequency of the PWM 1and PWM 2 drivers.

Each driver base frequency is divided by the va lue of the re spective PW M Divide R egister to de termi ne

the final frequency. The duty cycle settings are not affected by these settings, only the final frequency

of the PWM driver. A value of 00h will be decoded as 01h.

6.25 Fan Configuration 1 Registers

The Fan Configuration 1 Register controls the general opera tion of the RPM based Fan Speed Control

Algorithm used for the Fan 1 driver.

Bit 7 - EN_ALGO - enables the RPM based Fan Speed Control Algorithm. This bit is set and cleared

automatically when the LUT_LOCK bit is set based on the setting of the TACH / DRIVE bit (see

Section 6.35). When the LUT_LOCK bit is cleared, then setting this bit will enable the FSC without

using the Look Up Table.

‘0’ - (default) the control circuitry is disabled and the fan driver output is determined by the Fan

Driver Setting Register.

‘1’ - the control circuitry is enabled and the Fan Driver output will be automatically updated to

maintain the programmed fan speed as indicated by the TACH Target Register.

[2]

[3]

[4]

Table 6.30 PWM 1 and 2 Divide Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

41h R/W PWM 1 Divide 128 64 32 16 8 4 2 1 01h

81h R/W PWM 2 Divide 128 64 32 16 8 4 2 1 01h

Table 6.31 Fan Configuration 1 Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

42h R/W Fan 1

Configuration

1EN_

ALGO RANGE[1:0] EDGES[1:0] UPDATE[2:0] 2Bh

82h R/W Fan 2

Configuration

1EN_

ALGO RANGE[1:0] EDGES[1:0] UPDATE[2:0] 2Bh

Drive VALUE

255

---------------------

⎝⎠

⎛⎞

100%×=

Drive VALUE

255

---------------------

⎝⎠

⎛⎞

VDD×=

Drive VALUE

255

---------------------

⎝⎠

⎛⎞

VDD_5V×=

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Bits 6- 5 - RANGE[1:0] - Adjusts the range of reported and programmed tachometer reading values.

The RANGE bits determine the weighting of all TACH values (including the Valid TACH Count, TACH

Target, and TACH reading) as shown in Table 6.32.

Bits 4-3 - EDGES[1:0] - determines the minimum number of edges that must be detected on the

TACHx signal to determine a single rotation. A typical fan measured 5 edges (for a 2-pole fan). For

more accurate tachometer measurement, the min imum number of edges measured may be increased.

Increasing the number of edges measured with respect to the number of poles of the fan will cause

the TACH Reading registers to indicate a fan speed that is higher or lower than the actual speed. In

order for the FSC Algorithm to operate correctly, the TACH Target must be updated by the user to

accommodate this shift. The Effective Tach Mu ltiplier shown in Table 6.33 is used as a direct multiplier

term that is applied to the Actual RPM to achieve the Reported RPM. It should only be applied if the

number of edges measured does not match the number of edges expected based on the number of

poles of the fan (which is fixed for any given fan).

Contact SMSC for recommended settings when using fans with more or less than 2 poles.

Bit 2-0 - UPDATE - determines the base time between fan driver updates. The Update Time, along

with the Fan Step Register, is u sed to control the ramp rate of the drive resp onse to provide a cleaner

transition of the actual fan operation as the desired fan speed changes. The Update Time is set as

shown in Table 6.34.

Table 6.32 Range Decod e

RANGE[1:0] REPORTED MINIMUM

RPM TACH COUNT

MULTIPLIER10

005001

0 1 1000 (default) 2

1 0 2000 4

1 1 4000 8

Table 6.33 Minimum Edges for Fan Rotation

EDGES[1:0] MINIMUM TACH

EDGES NUMBER OF FAN POLES

EFFECTIVE TACH

MULTIPLIER (BASED ON 2

POLE FANS)10

00 3 1 pole 0.5

0 1 5 2 poles (default) 1

1 0 7 3 poles 1.5

11 9 4 poles 2

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6.26 Fan Configuration 2 Registers

The Fan Configuration 2 Register controls the tachometer measurement and advanced features of the

RPM based Fan Speed Control Algorithm.

Bit 6 - EN_RRCx - Enables ramp rate control when the corresponding fan driver is operated in the

Direct Setting Mode or the Direct Setting with LUT mode.

‘0’ (default) - Ramp ra te control is disabled. When the fan drive r is ope rati ng i n Direct Setting mode

or Direct Setting with LUT mode, the fan setting will instantly transition to the next programmed

setting.

‘1’ - Ramp rate control is e nabled. W hen the fa n d river is operating in Direct Setting mode or Direct

Setting with LUT mode, the fan drive setting will foll ow the ra mp rate controls as determined by the

Fan Step and Update Time settings. The maximum fan drive setting step is capp ed at the Fan St ep

setting and is updated based on the Update Time as given by Table 6.34.

Bit 5 - GLITCH_ENx - Disables the low pass glitch filter that removes high frequency noise injected

on the TACHx pi n. If the LOWDRIVE bit is set, this bit is ignored and the filter is automatically disabled.

‘0’ - The glitch filter is disabled.

‘1’ (default) - The glitch filter is enabled.

Bits 4 - 3 - DER_OPTx[1:0] - Control some of the advanced options that affect the derivative portion

of the RPM based Fan Speed Control Algorithm as shown in Table 6.36.

Table 6.34 Update Time

UPDATE[2:0]

UPDATE TIME 21 0

00 0 100ms

00 1 200ms

01 0 300ms

0 1 1 400ms (default)

10 0 500ms

10 1 800ms

1 1 0 1200ms

1 1 1 1600ms

Table 6.35 Fan Configuration 1 Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

43h R/W Fan 1

Configuration

2-EN_

RRC1 GLITCH

_EN1 DER_OPT1 [1:0] ERR_RNG[1:0] LOWD

RIVE1 38h

83h R/W Fan 2

Configuration

2-EN_

RRC2 GLITCH

_EN2 DER_OPT2 [1:0] ERR_RNG[1:0] LOWD

RIVE2 38h

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Bit 2 - 1 - ERR_RNGx[1:0] - Control some of the advanced options that affect the error window. When

the measured fan spe ed is within the programmed error windo w around the target speed, then the fan

drive setting is not updated. The algorithm will continue to monitor the fan speed and calculate

necessary drive setting changes based on the error, however these changes are ignored.

Bit 0 - LOWDRIVEx - Determines whether the tachometer measurement circu it will use the Tach Period

Measurement method of fan speed measurement or the Tach Pulse Count Method of fan speed

measurement. Setting this bit allows the use of low side fan drive circuits as shown in Figure 6.1

without requiring additional tachometer recovery circuitry.

‘0’ (default) - The tachometer signal must always be present when measuring the fan speed

regardless of the measurement method.

‘1’ - Low side PWM drive circuits are supported and the tachometer signal does not need to be

present at all times (which is common with such drive techniques). The tachometer measurement

circuitry will use the Tach Pulse Count Method to determine the fan speed (contact SMSC for

details on this operation). All tachometer related data is in the form of edge counts over a fixed

time period. This method is significantly slower and the tachometer updates are non-continuous.

Table 6.36 Derivative Options

DER_OPTX[1:0]

OPERATION10

0 0 No derivative options used

Basic derivative. The derivative of the error from

the current drive setting and the target is added

to the iterative Fan Drive Register setting (in

addition to proportional and integral terms)

Step derivative. The derivative of the error from

the current drive setting and the target is added

to the iterative Fan Drive Register setting and is

not capped by the Fan Step Register.

Both the basic derivative and the step derivative

are used effectively causing the derivative term to

have double the effect of the derivative term

(default).

Table 6.37 Error Range Options

ERR_RNGX[1:0]

OPERATION10

0 0 0 RPM (default)

0 1 50 RPM

1 0 100 RPM

1 1 200 RPM

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6.27 Gain Registers

The Gain Register stores the gain terms used by the proportional and integral portions of each of the

RPM based Fan Speed Control Algorithms. These gain terms are used as the KD, KI, and KP gain

terms in a classic PID control solution.

Figure 6.1 LOWDRIVE Supported Drive Circuit

Table 6.38 Gain Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

45h R/W Gain 1

85h R/W Gain 2

Table 6.39 Gain Decode

GAIND OR GAINP OR GAINI [1:0]

RESPECTIVE GAIN FACTOR10

00 1x

01 2x

1 0 4x (default)

11 8x

PWM Input

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6.28 Fan Spin Up Configuration Registers

The Fan Spin Up Configuration Register controls the settings of Spin Up Routine. The Fan Spin Up

Configuration Register is software locked.

Bit 7 - 6 - DRIVE_FAIL_CNTx[1:0] - Determines how many update cycles are used for the Drive Fail

detection function as shown in Table 6.41. This circuitry determines whether the fan can be driven to

the desired tach target.

Bit 5 - NOKICKx - Determines if the Spin Up Routine will drive the fan to 100% duty cycle for 1/4 of

the programmed spin up time before driving it at the programmed level.

‘0’ (default) - The Spin U p Routine will drive the fan driver to 100% for 1/4 of the prog rammed spin

up time before reverting to the programmed spin level.

‘1’ - The Spin Up Routine will not drive the fan driver to 100%. It will set the drive at the

programmed spin level for the entire duration of the programmed spin up time.

Bits 4 - 2 - SPIN_LVL[2:0] - Determines the final drive level that is used by the Spin Up Routine as

shown in Table 6.42.

Table 6.40 Fan Spin Up Configuration Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

46h R/W Fan 1 Spin Up

Configuration DRIVE_FAIL

_CNT1 [1:0] NOK

ICK1 SPIN_LVL[2:0] SPINUP_TIM

E [1:0] 0Dh

86h R/W Fan 2 Spin up

Configuration DRIVE_FAIL

_CNT2 [1:0] NOK

ICK2 SPIN_LVL[2:0] SPINUP_TIM

E [1:0] 0Dh

Table 6.41 DRIVE_FAIL_CNT[1:0] Bit Decode

DRIVE_FAIL_CNT[1:0]

NUMBER OF UPDATE PERIODS10

Disabled - the Drive Fail detection circuitry is

disabled (default)

16 - the Drive Fail detection circuitry will count for 16

update periods

32 - the Drive Fail detection circuitry will count for 32

update periods

64 - the Drive Fail detection circuitry will count for 64

update periods

Table 6.42 Spin Level

SPIN_LVL[2:0]

SPIN UP DRIVE LEVEL210

0 0 0 30%

0 0 1 35%

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Bit 1 -0 - SPINUP_TIME[1:0] - determines the maximum Spin Time that the Spin Up Routine will run

for (see Section 6.9). If a valid tachometer measurement is not detected before the Spin Time has

elapsed, then an interrupt will be generated. When the RPM based Fan Speed Control Algorithm is

active, the fan driver will attempt to re-start the fan immed iatel y af ter the en d of the last spin up attemp t.

The Spin Time is set as shown in Table 6.43.

6.29 Fan Step Registers

The Fan Step Registe rs, along with the Update Time, controls the ramp rate of the fan drive r response

calculated by the RPM based Fan Speed Control Algorithm. The value of the registers represents the

maximum step size each fan driver will take between update times (see Section 6.25).

When the FSC algorithm is enabled, Ramp Rate control is automatically used. When the FSC is not

active, then Ramp Rate control can be enabled by asserting the EN_RRC bit (see Section 6.26)

0 1 0 40%

0 1 1 45%

1 0 0 50%

1 0 1 55%

1 1 0 60% (default)

1 1 1 65%

Table 6.43 Spin Time

SPINUP_TIME[1:0]

TO TA L SP I N U P TI M E10

0 0 250 ms

0 1 500 ms (default)

1 0 1 sec

1 1 2 sec

Table 6.44 Fan Step Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

47h R/W Fan 1 Max

Step - - 32 16 8 4 2 1 10h

87h R/W Fan 2 Max

Step - - 32 16 8 4 2 1 10h

Table 6.42 Spin Level (continued)

SPIN_LVL[2:0]

SPIN UP DRIVE LEVEL210

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APPLICATION NOTE: The UPDATE bits and Fan Step Register settings operate independently of the RPM based

Fan Speed Control Algorithm and will always limit the fan drive setting. That is, if the

programmed fan drive setting (either in determined by the RPM based Fan Speed Control

Algorithm, the Look Up Table, or by manual settings) exceeds the current fan drive setting

by greater than the Fan Step Register setting, the EMC2106 will limit the fan drive change

to the value of the Fan Step Register. It will use the Update Time to determine how often to

update the drive settings.

APPLICATION NOTE: If the Fan Speed Control Algorithm is used, the default settings in the Fan Configuration 2

The Fan Step Registers are software locked.

6.30 Fan Minimum Drive Registers

The Fan Minimum Drive Register stores the minimum drive setting for each RPM based Fan Speed

Control Algorith m. The RPM based Fan Speed Co ntrol Algorithm will not drive the fan a t a level lower

than the minimum drive unless the target Fan Speed is set at FFh (see Section 6.33)

During normal operation, if the fan stops for any reason (including low drive), the RPM based Fan

Speed Control Algorithm will attempt to restart the fan. Setting the Fan Minimum Drive Registers to a

setting that will maintain fan operation is a useful way to avoid potential fan oscillations as the control

circuitry attempts to drive it at a level that cannot support fan operation.

The Fan Minimum Drive Register is software locked.

6.31 Valid TACH Count Registers

The Valid TACH Count Register stores the maximum TACH Reading Register value to indicate that

the each fan is spinning properly. The value is referenced at the end of the Spin Up Routine to

determine if the fan has started operating and decide if the device needs to retry. See Equation [5] for

translating the count to an RPM. This register is only used when the FSC is active.

Table 6.45 Minimum Fan Drive Registers

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

48h R/W Fan 1

Minimum

Drive 128643216 8 4 2 1 66h

(40%)

88h R/W Fan 2

Minimum

Drive 128643216 8 4 2 1 66h

(40%)

Table 6.46 Valid TACH Count Registers

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

49h R/W Valid T ACH

Count 1 4096 2048 1024 512 256 128 64 32 F5h

89h R/W Valid T ACH

Count 2 4096 2048 1024 512 256 128 64 32 F5h

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If the TACH Reading Register value exceeds the Valid TACH Count Register (indicating that the Fan

RPM is below the threshold set by this count), then a stalled fan is detected. In this condition, the

algorithm will automatically begin its Spin Up Routine.

If a TACH Target setting is set above the Valid TACH Count setting, then that setting will be ignored

and the algorithm will use the current fan drive setting.

The Valid TACH Count Register is software locked.

6.32 Fan Drive Fail Band Registers

The Fan Drive Fail Band Registers store the number of tach counts used by the Fan Drive Fail

detection circuitry. This circuitry is activated when the fan drive setting high byte is at FFh. When it is

enabled, the actual measured fan speed is compared against the target fan speed. These registers

are only used when the FSC is active.

This circuitry is used to indicate that the target fan speed at full drive is higher than the fan is actually

capable of reaching. If the measured fan speed does not exceed the target fan speed minus the Fan

Drive Fail Band Register settings for a period of time longer than set by the DRIVE_FAIL_CNTx[1:0]

bits then the DRIVE_FAIL status bit will be set and an interrupt generated.

6.33 TACH Target Registers

Table 6.47 Fan Drive Fail Band Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

4Ah R/W Fan 1 Drive

Fail Band

Low Byte 16 8 4 2 1 - - - 00h

4Bh R/W Fan 1 Drive

Fail Band

High Byte 4096 2048 1024 512 256 128 64 32 00h

8Ah R/W Fan 2 Drive

Fail Band

Low Byte 16 8 4 2 1 - - - 00h

8Bh R/W Fan 2 Drive

Fall Band

High Byte 4096 2048 1024 512 256 128 64 32 00h

Table 6.48 TACH Target Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

4Ch R/W TACH Target

1 Low Byte 168421- - - F8h

4Dh R/W T ACH Target

1 High Byte 4096 2048 1024 512 256 128 64 32 FFh

8Ch R TACH Target

2 Low Byte 168421- - - F8h

8Dh R/W TACH Target

2 High Byte 4096 2048 1024 512 256 128 64 32 FFh

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The TACH Target Reg isters hold the target tachometer value that is maintained each of the RPM based

Fan Speed Control Algorithms.

The value in the TACH Target Registers will always reflect the current TACH Target value. If the Look

Up Tabl e is active and configured to operate in RPM Mode, then this register will be read only. Writing

to this register will have no affect and the data will not be stored.

If one of the algorithms is enabled then setting the TACH Target Register to FFh will disable the fan

driver (set the fan drive setting to 0%). Setting the TACH Target to any other value (from a setting of

FFh) will cause the algorithm to invoke the Spin Up Routine after which it will function normally.

The Tach Target is not applied until the high byte is written. Once the high byte is written, the current

value of both high and low bytes will be used as the next Tach target. 3

6.34 TACH Reading Registers

The TACH Reading Registers’ contents describe the current tachometer reading for each of the fan.

By default, the data represents the fan speed as the number of 32kHz clock periods that occur for a

single revolution of the fan.

Equation [5] sho ws the detailed conversion from TACH measurement (COUNT) to RPM while Equation

[6] shows the simplified translation of TACH Reading Register count to RPM assuming a 2-pole fan,

measuring 5 edges, with a frequency of 32.768kHz. T hese equ ations ar e solved and tabulated for ease

of use in AN17.4 RPM to TACH Counts Conversion.

Whenever the high byte register is read, the corresponding low byte data will be loaded to internal

shadow registers so that when the low byte is read, the data will always coincide with the previously

read high byte.

Table 6.49 TACH Reading Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

4Eh R Fan 1 TACH 4096 2048 1024 512 256 128 64 32 FFh

4Fh R Fan 1 TACH

Low Byte 168421- - - F8h

8Eh R Fan 2 TACH 4096 2048 1024 512 256 128 64 32 FFh

8Fh R Fan 2 TACH

Low Byte 168421- - - F8h

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6.35 Look Up Table Configuration Registers

The Look Up Table Configuration Register holds the setup information for the two temperature to fan

drive look up tables.

Bit 7 - USE_DTS_F1 or USE_DTS_F3 - This bit determines whether the Pushed Temperature 1 or

Pushed Temperature 3 registers are using DTS data.

‘0’ (default) - The Pushed Temperature 1 or Pushed Temperature 3 registers are not using DTS

data. The contents of these registers are standard 2’s complement temperature data.

‘1’ - The Pushed Temperature 1 or Pu shed Temperat ure 3 registers are loaded with DTS data. The

contents of these registers are automatically subtracted from a fixed value of 100°C before they

are compared to the Look Up Table threshold levels.

Bit 6 - USE_DTS_F2 or USE_DTS_F4 - This bit determines whether the Pushed Temperature 2 or

Pushed Temperature 4 Registers are using DTS data.

‘0’ (default) - The Pushed Temperature 2 or Pushed Temperature 4 registers are not using DTS

data. The contents of these registers are standard 2’s complement temperature data.

‘1’ - The Pushed Temperature 2 or Pu shed Temperat ure 4 registers are loaded with DTS data. The

contents of these registers are automatically subtracted from a fixed value of 100°C before they

are compared to the Look Up Table threshold levels.

Bit 5 - LUT_LOCK - Thi s bit locks upda ting the Look Up Table entri es and determines wheth er the look

up table is being used.

‘0’ (default) - The Look Up Table entries can be updated normally. The Look Up Table will not be

used while the Look Up Table entries are unlocked. During this condition, the fan drive output will

not change states regardless of temperature or tachometer variation.

where:

[5]

poles = number of poles of the fan

(typically 2)

fTACH = the tachometer

measurement frequency (typically

32.768kHz)

n = number of edges measured

(typically 5 for a 2 pole fan)

m = the multiplier defined by the

RANGe bits [6]

COUNT = TACH Reading Register

value (in decimal)

Table 6 .50 Look Up Table Configur ation Registers

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

50h R/W LUT 1

Configuration USE_D

TS_F1 USE_D

TS_F2 LUT_L

OCK TACH /

DRIVE TEMP3_CFG

[1:0] TEMP4_CFG

[1:0] 00h

90h R/W LUT2

Configuration USE_D

TS_F3 USE_D

TS_F4 LUT_L

OCK TACH /

DRIVE TEMP3_CFG

[1:0] TEMP4_CFG

[1:0] 00h

RPM 1

poles()

-------------------- n1–()

COUNT 1

-----

----------------------------------fTACH 60×××=

RPM 3,932,160 m×

COUNT

--------------------------------------

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‘1’ - The Look Up Table entries are locked and cannot be updated. The Look Up Table is fully active

and will be used based on the loaded values. The fan drive output will be updated depending on

the temperature and / or TACH variations.

APPLICATION NOTE: When the LUT_LOCK bit is set at a logic ‘0’, the fan drive setting will be set at whatever

value was last used by the RPM based Fan Speed Control Al gorithm or the Look Up Table.

Bit 4 - TACH / DRIVEx - This bit selects the data format for the LUT drive settings.

‘0’ (default) - The Look Up Table drive settings are RPM TACH count values for use by the RPM

based Fan Speed Control Algorithm. The Look Up Table drive settings should be loaded highest

value to lowest value (to coincide with the inversion between TACH counts and actual RPM).

‘1’ - The Look Up Table drive settings are fan drive setting valu es and are used directly. Th e drive

settings should be loaded lowest value to highest value.

APPLICATION NOTE: The TACH / DRIVE bit should be set prior to the LUT_LOCK bit being set so that, if the fan

driver is disabled, the output drive is in the proper state.

Bits 3-2 - TEMP3_CFG[1:0] - These bits determine the temperature channel that is used for the

Temperature 3 inputs to the Look Up Table as shown in Table 6.51.

Bits 1-0 - TEMP4_CFG[1:0] - These bits determine the temperature channel that is used for the

Temperature 4 inputs to the Look Up Table as shown in Table 6.52.

APPLICATION NOTE: When any of the External Diode 1, External Diode 2, and External Diode 3 channels are

configured to operate as voltage inputs, the voltage data is used in the Look Up Table instead

of the corresponding temperature data. Therefore, the threshold settings must be updated

accordingly. All voltage channels (including VIN1, VIN2, and VIN3) are assumed to be

increasing (i.e. a larger voltage reading indicates a higher fan speed).

Table 6.51 TEMP3_CFG Decode

TEMP3_CFG [1:0]

TEMPERATURE CHANNEL USED10

0 0 External Diode 3 (default)

0 1 TRIP_SET / VIN4 Voltage

10 Pushed Temperature 1 (LUT1)

Pushed Temperature 3 (LUT2)

1 1 Reserved

Table 6.52 TEMP4_CFG Decode

TEMP4_CFG [1:0]

TEMPERATURE CHANNEL USED10

0 0 Internal Diode (default)

0 1 External Diode 4

10 Pushed Temperature 2 (LUT1)

Pushed Temperature 4 (LUT2)

11 Reserved

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6.36 Look Up Table 1 Registers

Table 6.53 Look Up Table 1 Registers

ADDR R/W REGISTER TACH /

DRIVEB7B6B5B4B3B2B1B0DEFAULT

51h R/W LUT 1 Drive

Setting 1 ‘0’ 4096 2048 1024 512 256 128 64 32 FBh

‘1’ 128 64 32 16 8 4 2 1

52h R/W

LUT 1 Ext

Diode 1

Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1 VIN1

Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

53h R/W

LUT 1 Ext

Diode 2

Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1 VIN2

Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

54h R/W

LUT 1 Temp

3 Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1

Voltage 3

Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

55h R/W LUT 1 Temp

4 Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

... ... ... ... ... ... ... ... ... ... ... ... .. .

74h R/W LUT 1 Drive

Setting 8 ‘0’ 4096 2048 1024 512 256 128 64 32 92h

‘1’ 128 64 32 16 8 4 2 1

75h R/W

LUT 1 Ext

Diode 1

Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1 VIN1

Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

76h R/W

LUT 1 Ext

Diode 2

Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1 VIN2

Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

77h R/W

LUT 1 Temp

3 Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT 1

Voltage 3

Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

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DATASHEET

The Look Up Table 1 Registers hold the 40 entries of the Loo k Up Table that contro ls the drive of Fan

1. As the temperature (or voltage) channels are updated, the measured value for each channel is

compared against the respective entries in the Look Up Table and the associated drive setting is

loaded into an internal shadow register and stored.

The bit weighting for temperature inputs represents °C and is compared against the measured data.

Note that the LUT entry does not include a sign bit. The Look Up Table does not support negative

temperature values and the MSBit should not be set for a temperature input.

The bit weighting for voltage inputs represents mV above 0V and is compared against the measured

data.

Each temperature (or voltage) channel threshold shares the same hysteresis value. When the

measured temperature for any of the channels meets or exceeds the programmed thresh old, the drive

setting associated with that threshold is used. The temperature must drop below the threshold minus

the hysteresis value before the drive setting will be set to the previous value.

APPLICATION NOTE: For proper operation, the hysteresis must be smaller than the difference between two

consecutive thresholds.

If the RPM based Fan Speed Control Algorithm is used, the TACH Target is updated after every

conversion. It is always set to the minimum TACH Target th at is stored by the Look Up Table. The fan

drive setting cycle is updated based on the RPM based Fan Speed Control Algorithm configuration

settings.

If the RPM based Fan Speed Control Algorithm is no t used, then the fan drive setting is updated after

every conversion. It is set to the maximum duty cycle that is stored by the Look Up Table.

6.37 Look Up Table 2 Registers

78h R/W LUT 1 Temp

4 Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

79h R/W LUT 1 Temp

Hysteresis X - - -168421 0Ah

Table 6.54 Look Up Table2 Registers

ADDR R/W REGISTER TACH /

DRIVEB7B6B5B4B3B2B1B0DEFAULT

91h R/W LUT 2 Drive

Setting 1 ‘0’ 4096 2048 1024 512 256 128 64 32 FBh

‘1’ 128 64 32 16 8 4 2 1 FBh

92h R/W

LUT 2 Ext

Diode 1

Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 VIN1

Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

Table 6.53 Look Up Table 1 Registers (continued)

ADDR R/W REGISTER TACH /

DRIVEB7B6B5B4B3B2B1B0DEFAULT

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The Look Up Table 2 Registers hold the 40 entries of the Loo k Up Table that contro ls the drive of Fan

2. As the temperature (or voltage) chan nels are updated, the measured temperature for each channel

is compared against the respective entries in the Look Up Table and the associated drive setting is

loaded into an internal shadow register and stored.

93h R/W

LUT 2 Ext

Diode 2

Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 VIN2

Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

94h R/W

LUT 2 Temp

3 Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 Voltage

3 Setting 1 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

95h R/W LUT2 Temp 4

Setting 1 X - 64 32 16 8 4 2 1 7Fh

(127°C)

... ... ... ... ... ... ... ... ... ... ... ... ...

B4h R/W LUT 2 Drive

Setting 8 ‘0’ 4096 2048 1024 512 256 128 64 32 92h

‘1’ 128 64 32 16 8 4 2 1

B5h R/W

LUT 2 Ext

Diode 1

Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 VIN1

Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

B6h R/W

LUT 2 Ext

Diode 2

Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 VIN2

Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

B7h R/W

LUT 2 Temp

3 Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

LUT2 Voltage

3 Setting 8 X 752.9 376.5 188.2 94.12 47.06 23.53 11.76 5.88 7Fh

(0.4V)

B8h R/W LUT2 Temp 4

Setting 8 X - 64 32 16 8 4 2 1 7Fh

(127°C)

B9h R/W LUT 2 Temp

Hysteresis X - - -168421 0Ah

Table 6.54 Look Up Table2 Registers (continued)

ADDR R/W REGISTER TACH /

DRIVEB7B6B5B4B3B2B1B0DEFAULT

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6.38 Muxed Pin Configuration Register

The Muxed Pin Configuration Register controls the pin function for all of the multiple function GPIO

pins.

Bit 7 - PWM1_EN - Enables the OVERT1# / PWM1 pin as a PWM output.

‘0’ (default) - The OVERT1# / PWM1 pin acts as a dedicated interrupt pin for the External Diode

1 channel. All PWM1 controls will be ignored though can be updated normally.

‘1’ - The OVERT1# / PWM1 pin acts as a PWM outpu t. The High Side Fan Driver will be disabled.

Bit 6 - 5 - GPIO5_CFG[1:0] - Determines the pin function for the OVERT3# / GPIO5 / PWM4 pin as

shown in Table 6.56. W hen not configured as a PWM output, all PWM4 controls will be ignored though

can be updated normally.

Bits 4 - 3 - GPIO4_CFG[1:0] - Determines the pin functions for the OVERT2# / GPIO4 / PWM3 pin as

shown in Table 6.57. W hen not configured as an output, all PW M3 controls will be ignored though can

be updated normally.

Table 6.55 Muxed Pin Configuration Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E0h R/W Muxed Pin

Config PWM1

_EN GPIO5

_CFG1 GPIO5_

CFG0 GPIO4_

CFG1 GPIO4

_CFG0 GPIO3

_CFG GPIO2

_CFG GPIO1

_CFG 01h

Table 6.56 GPIO5_CFG[1:0] Decode

GPIO5_CFG[1:0]

OVERT3# / GPIO5 / PWM4 PIN FUNCTION10

OVERT3# - the pin will act as a dedicated alert for the External

Diode 2 channel (default)

0 1 GPIO - the pin will act as a GPIO

1 0 GPIO - the pin will act as a GPIO

PWM - the pin will act as a PWM output controlled by the PWM4

Setting Register

Table 6.57 GPIO4_CFG[1:0] Decode

GPIO4_CFG[1:0]

OVERT2# / GPIO4 / PWM3 PIN FUNCTION10

OVERT2# - the pin will act as a dedicated alert for the External

Diode 2 channel (default)

0 1 GPIO - the pin will act as a GPIO

1 0 GPIO - the pin will act as a GPIO

PWM - the pin will act as a PWM output controlled by the PWM3

Setting Register

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Bit 2 - GPIO3_CFG - Determines the pin function for the PWM2 / GPIO3 pin as well as the DAC2 pin.

‘0’ (default) - The PWM2/ GPIO3 pin functions as a PWM output for the 2nd the RPM based Fan

Speed Control Algorithm (FSC). The Linear DAC Fan Driver is disabled and the DAC2 pin will be

in a high impedance state.

‘1’ - The PWM2 / GPIO3 pin functions as a GPIO. The Linear DAC Fan Driver is enabled and

driven by the 2nd RPM based Fan Speed Control Algorithm (FSC). All PWM2 controls will be

ignored though are still writable via the SMBus.

Bit 1 - GPIO2_CFG - Determines the pin functions for the TACH2 / GPIO2 pin.

‘0’ (default) - The TACH2 / GPIO2 pin function s as a tachometer input for the 2 nd the RPM based

Fan Speed Control Algorithm (FSC).

‘1’ - The TACH2 / GPIO2 pin functions as a GPIO. When set, the EN_ALGO2 bit will automatically

be set to ‘0’ and cannot be set.

Bit 0 - GPIO1_CFG - Determines the pin function for the CLK_IN / GPIO1 pin.

‘0’ - The CLK_IN / GPIO1 pin functions as a clock input for the RPM based Fan Speed Control

Algorithm (FSC).

‘1’ (default) - The CLK_IN / GPIO1 pin functions as a GPIO.

6.39 GPIO Direction Register

The GPIO Direction Register 1 controls the direction of GPIOs 1 through 6. When muxable pins are

not configured as a GPIO ports the respective bits are ignored.

Bit 5 - 0 - GPIOx_DIR - Controls the input / output state of GPIOs. The bit is not used if the pin is not

configured as a GPIO.

‘0’ (default) - The GPIO is configured as an input.

‘1’ - The GPIO is configured as an output.

6.40 GPIO / PWM Pin Output Configuration Register

The GPIO Output Configuration Re gister controls th e output pin type o f each GPIO pin. These settings

apply to the pin if it is configured as a GPIO output or a PWM. These bits do not apply if the pin is

configured as a DAC outp ut or one of th e three dedi cate d OVERTx pins (wh ich are always o pen drain ).

Bit 6 - PWM1_OT - Determines the output type for the PWM1 pin.

Table 6.58 GPIO Direction Register

ADDRR/WREGISTERB7B6B5B4B3B2B1B0DEFAULT

E1h R/W GPIO

Direction 1 --

GPIO

6_DIR GPIO

5_DIR GPIO

4_DIR GPIO

3_DIR GPIO

2_DIR GPIO

1_DIR 00h

Table 6.59 GPIO / PWM Pin Output Configuration Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E2 R/W GPIO

Output

Config -PWM

1_OT GPIO

6_OT GPIO

5_OT GPIO

4_OT GPIO

3_OT GPIO

2_OT GPIO

1_OT 00h

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‘0’ (default) - The PWM1 output is configured as an open drain output (if enabled as a PWM

output).

‘1’ - The PWM1 output is configured as a push-pull output (if enabled as an a PWM output).

Bit 5 - 0 - GPIOx_OT - Determines the output type for GPIOx.

‘0’ (default) - GPIOx is configured as an open drain output (if enabled as an output).

‘1’ - GPIOxis configured as a push-pull output (if enabled as an output).

6.41 GPIO Input Register

The GPIO Input Register indicates the state of the corresponding GPIO pin regardless of the

functionality of the pin (GPIO, PWM, or TACH) or the direction of the GPIO (input, push-pull output,

open-drain output). When a GPIO is configured as an input, any change of state will assert the

ALERT# pin (unless GPIO interrupts are masked, see Section 6.15).

6.42 GPIO Output Register

The GPIO Output Register controls th e state of the corresponding GPIO pins when they areconfigu red

as GPIOs and as outputs.

If the output is configured as an open-drain output, then it requires a pull-up resistor to VDD. Setting

the corresponding bit to a ‘ 1’ will act to disab le the output allowing the pu ll-up resistor to pull the output

high. Setting the correspondin g bit to a ‘0’ will enable the output and drive the pin to a logical ‘0’ state.

If the output is configured as a push-pull output, then output pin will immediately be driven to match

the corresponding bit setting.

6.43 GPIO Interrupt Enable Register

Table 6.60 GPIO Input Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E3h R GPIO Input - - GPIO

6_IN GPIO

5_IN GPIO

4_IN GPIO

3_IN GPIO

2_IN GPIO

1_IN 00h

Table 6.61 GPIO Output Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E4h R/W GPIO

Output 1 --

GPIO6_

OUT GPIO5_

OUT GPIO4_

OUT GPIO3

_OUT GPIO2

_OUT GPIO1

_OUT 00h

Table 6.62 GPIO Interrupt Enable Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E5h R/W GPIO

Interrupt

Enable --

GPIO6_

INT_EN GPIO5_

INT_EN GPIO4_

INT_EN GPIO3_

INT_EN GPIO2_

INT_EN GPIO1_

INT_EN 00h

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The GPIO Interrupt Enable Register enables the GPIOs to assert the ALERT pin when they change

state. When the GPIO pins are disabled or configured as outputs, then these bits are ignored.

Bit 5 - 0 - GPIOx_INT_EN - Allows the ALERT# pin to be asserted when the GPIOx pin changes state

(when configured as an input).

‘0’ (default) - The ALERT# pin will not be asserted when the GPIOx pin changes state (when

configured as an input).

‘1’ - The ALERT# pin will be asserted when the GPIOxpin changes state (when configured as an

input).

6.44 GPIO Status Register

The GPIO Status Register indicates which GPIO has changed states to cause the ALERT pins to be

asserted. This register is cleared when it is read. The bits in this register are set whenever the

corresponding GPIO changes states regardless if the ALERT pins are asserted. Once a bit is set, it

will remain set until read.

If any bit in this register is set, then the GPIO status bit will be set.

Bit 5 - 0 - GPIOx_STS - Indicates that the GPIOx pin has changed states from a ‘0’ to a ‘1’ or a ‘1’ to

a ‘0’ (when configured as a GPIO input).

6.45 Software Lock Register

The Software Lock Register controls the software locking of critical registers. This register is software

locked.

Bit 0 - LOCK - this bit acts on all registers that are designated SWL. When this bit is set, the locked

registers become read only and cannot be updated.

‘0’ (default) - all SWL registers can be updated normally.

‘1’ - all SWL registers cannot be updated and a hard-reset is required to unlock them.

Table 6.63 GPIO Status Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

E6h R-C GPIO

Status --

GPIO6_

STS GPIO5_

STS GPIO4_

STS GPIO3_

STS GPIO2_

STS GPIO1_

STS 00h

Tab le 6.64 Software Lock Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

EFh R/W Software

Lock - - - - - - - LOCK 00h

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DATASHEET

6.46 Product Features Register

The Product Features Register indicates which pin selected functionality is enabled.

Bit 1 - 0 - SHDN_SEL[1:0] - Ind icates wh at the d etected p in state of the SHDN _SEL p in was an d which

functions are enabled.

6.47 Product ID Register

The Product ID Register contains a unique 8 bit word that identifies the product.

6.48 Manufacturer ID Register

The Manufacturer ID Register contains a 8 bit word that identifies SMSC.

Table 6.65 Product Features Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

FCh R Product

Features - - - - - - SHDN_SEL[1:0] 00h

Table 6.66 SHDN_SEL Bit Decode

FUN_SEL[1:0]

EXTERNAL DIODE 1 MODE

CRITICAL / THERMAL

SHUTDOWN

TEMPERATURE RANGE VIN4 OR

TRIP_SET10

Transistor mode - Beta =

automatic

REC = enabled High range - 92°C to 154°C TRIP_SET

01 Diode mode -

B e ta = 1111 b

REC = disabled Low Range

60°C to 122°C TRIP_SET

10 Not used -

Internal diode linked to

Hardware Thermal / Critical

Shutdown circuitry

Low Range

60°C to 122°C TRIP_SET or VIN4

(see Section 6.1.2)

Table 6.67 Product ID Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

FDh R Product ID

Table 6.68 Manufacturer ID Reg iste r

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

FEh R Manufacturer ID 0 1 0 1 1 1 0 1 5Dh

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6.49 Revision Register

The Revision Register contains a 8 bit word that identifies the die revision.

Table 6.69 Revision Register

ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT

FFh R Revision 0 0 0 0 0 0 1 0 02h

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Chapter 7 Package Drawing

7.1 QFN 28-Pin 5mm x 5mm

Figure 7.1 EMC2106 28-Pin 5x5mm QFN Package Outline and Parameters

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DATASHEET

7.2 Package Markings

All devices will be marked on the first line of the top side with “2106”. On the second line, they will be

marked with the Functional Revision “C”, followed by “YWW-AC26”. On the third line, they will be

marked with the Lot Number, and on the fourth line, they will be marked with the Vendor and Country

Codes.

Figure 7.2 EMC2106 Package Marking

BOTTOM

BOTTOM MARKING NOT ALLOWED

Line 1 – SMS C Logo

Line 2 – Device Number, Version

Line 3 - Revision, Year, Week, 4-digit Engineering Code (RYYW W X XXX)

Line 4 – Lot Number

LINES 5: BEST FIT BETWEEN

PIN 1 MARK AND Pb-FREE SYMBOL

PB-FREE/GREEN SYMBOL

(M a tte S n )

0.4

4x 1.3PT

TOP

PIN 1

MINIMUM CIRCLE “R”

DIAMETER = 0.80mm

Line 5 – Vendor ID and Country Code (VV – CC ) LINES 1, 2, 3, & 4: CEN TER

HORIZONTAL ALIGNMENT

2106

RY WWAC2 6

8H123456a

VV - CC

-1

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Appendix A Thermistors

The EMC2106 can monitor thermistor inputs on the TRIP_SET / VIN4 as well as supporting a

thermistor option on the all of the external diode pins pairs (DP1 / VREF_T1 and DN1 / VIN1,etc.).

The Thermistors can be connected as shown in Figure A.1.

Figure A.1 is representative of one of the thermistor channels and will apply to DP1 / VREF_T1 and

DN1 / VIN1, DP2 / VREF_T2 and DN2 / VIN2.

The top side resistor is internally integrated in t he case of the TR IP_SET / VIN4 chann el and the VREF

voltage will not be brought out externally. The Thermistor should be connected in the same way as

RSET.

The relationship between voltage and temperature is roughly linear. the measured voltage by the

EMC2106 will be inversely proportional to temperature .

Linearization methods can only accurately capture the temperature over a limited window of

temperatures.

For a 10k Ohm type 3370 Thermistor and a 1.2k ohm ±1% setting resistor, the output response

corresponding to a thermistor is tabulated in Table A.1.

If the INV_VINx bit is set then the results of the circuit (configured as shown in Figure A.1) is shown

in Table A.2.

The EMC2106 does not perform any numerical calculations on the thermistor value if a thermistor is

monitored on TRIP_SET / VIN4 pin. If the External Diode 1, External Diode 2, or External Diode 3

channels are configured to measure a thermistor, it must be configured as shown in Figure A.1.

When measuring a thermistor input with Fan Control Look Up Table, care must be taken that the

temperature thresholds are entered as a unsigned voltage number that corresponds to the desired

thermal threshold. Also note that the LUT assumes that the VIN1 and TRIP_SET / VIN4 voltage inputs

are directly proportional to temperature.

Figure A.1 “Low Side” Thermistor Connection

10K 1%

Thermistor

DP3 / DN4 / VREF_T3

DN3 / DP4 / VIN3

1.2K

0.1uF

EMC2104/5/6

ADC

Buffer Reference

Voltage

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A.1 Thermistor Look Up Tables

Table A.1 “Low Side” Thermistor Look Up Table

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE

-45 254 15 235 75 157 135 72

-44 253 16 235 76 155 136 71

-43 253 17 234 77 154 137 70

-42 253 18 233 78 152 138 69

-41 253 19 232 79 150 139 68

-40 253 20 231 80 148 140 67

-39 253 21 231 81 146 141 66

-38 253 22 230 82 145 142 65

-37 252 23 229 83 143 143 64

-36 252 24 228 84 141 144 63

-35 252 25 227 85 139 145 62

-34 252 26 226 86 138 146 61

-33 252 27 225 87 136 147 60

-32 252 28 224 88 135 148 59

-31 252 29 223 89 133 149 59

-30 252 30 222 90 131 150 58

-29 251 31 221 91 129 151 57

-28 251 32 220 92 128 152 56

-27 251 33 219 93 126 153 55

-26 251 34 218 94 124 154 54

-25 251 35 217 95 123 155 54

-24 251 36 216 96 121 156 53

-23 250 37 215 97 119 157 52

-22 250 38 213 98 118 158 51

-21 250 39 212 99 116 159 51

-20 250 40 211 100 114 160 50

-19 250 41 210 101 113 161 49

-18 249 42 208 102 111 162 48

-17 249 43 207 103 110 163 48

-16 249 44 206 104 108 164 47

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-15 249 45 205 105 106 165 46

-14 248 46 203 106 105 166 46

-13 248 47 202 107 103 167 45

-12 248 48 200 108 102 168 44

-11 247 49 199 109 100 169 44

-10 247 50 198 110 99 170 43

-9 247 51 196 111 97 171 43

-8 246 52 195 112 96 172 42

-7 246 53 193 113 95 173 41

-6 246 54 192 114 93 174 41

-5 245 55 190 115 92 175 40

-4 245 56 189 116 90 176 40

-3 245 57 187 117 89 177 39

-2 244 58 185 118 88 178 38

-1 244 59 184 119 86 179 38

0 243 60 182 120 85 180 37

1 243 61 181 121 84 181 37

2 243 62 179 122 82 182 36

3 242 63 177 123 81 183 36

4 242 64 176 124 80 184 35

5 241 65 174 125 79 185 35

6 241 66 172 126 82 186 34

7 240 67 171 127 81 187 34

8 240 68 169 128 80 188 33

9 239 69 167 129 78 189 33

10 238 70 166 130 77 190 32

11 238 71 164 131 76 191 32

12 237 72 162 132 75

13 237 73 160 133 74

14 236 74 159 134 73

Table A.1 “Low Side” Thermistor Look Up Table (continued)

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE

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Table A.2 Inverted Thermistor Look Up Table

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE

-45 0 15 19 75 97 135 182

-44 1 16 20 76 99 136 183

-43 1 17 20 77 100 137 184

-42 1 18 21 78 102 138 185

-41 1 19 22 79 104 139 186

-40 1 20 23 80 106 140 187

-39 1 21 23 81 108 141 188

-38 1 22 24 82 109 142 189

-37 2 23 25 83 111 143 190

-36 2 24 26 84 113 144 191

-35 2 25 27 85 115 145 192

-34 2 26 28 86 116 146 193

-33 2 27 29 87 118 147 194

-32 2 28 30 88 120 148 195

-31 2 29 31 89 121 149 195

-30 2 30 32 90 123 150 196

-29 3 31 33 91 125 151 197

-28 3 32 34 92 126 152 198

-27 3 33 35 93 128 153 199

-26 3 34 36 94 130 154 200

-25 3 35 37 95 131 155 200

-24 3 36 38 96 133 156 201

-23 4 37 39 97 135 157 202

-22 4 38 41 98 136 158 203

-21 4 39 42 99 138 159 203

-20 4 40 43 100 140 160 204

-19 4 41 44 101 141 161 205

-18 5 42 46 102 143 162 206

-17 5 43 47 103 144 163 206

-16 5 44 48 104 146 164 207

-15 5 45 50 105 148 165 208

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-14 6 46 51 106 149 166 208

-13 6 47 52 107 151 167 209

-12 6 48 54 108 152 168 210

-11 7 49 55 109 154 169 210

-10 7 50 56 110 155 170 211

-9 7 51 58 111 157 171 211

-8 8 52 59 112 158 172 212

-7 8 53 61 113 159 173 213

-6 8 54 62 114 161 174 213

-5 9 55 64 115 162 175 214

-4 9 56 65 116 164 176 214

-3 9 57 67 117 165 177 215

-2 10 58 69 118 166 178 216

-1 10 59 70 119 168 179 216

0 11 60 72 120 169 180 217

1 11 61 73 121 170 181 217

2 11 62 75 122 172 182 218

3 12 63 77 123 173 183 218

4 12 64 78 124 174 184 219

5 13 65 80 125 175 185 219

6 13 66 82 126 172 186 220

7 14 67 83 127 173 187 220

8 15 68 85 128 174 188 221

9 15 69 87 129 176 189 221

10 16 70 88 130 177 190 222

11 16 71 90 131 178 191 222

12 17 72 92 132 179

13 18 73 94 133 180

14 18 74 95 134 181

Table A.2 Inverted Thermisto r Look Up Table (continued)

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE T

(°C) ADC

CODE

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Appendix B Look Up Table Operation

The EMC2106 uses a look-up table to apply a user-programmable fan control profile based on

measured temperature to each fan driver. In this look-up table, each temperature channel is allowed

to control the fan drive output independently (or jointly) by programming up to eight pairs of

temperature and drive setting entries.

The user programs the look-up table based on the desired operation. If the RPM based Fan Speed

Control Algorithm is to be used (see Section 6.6), then th e user must program an RPM target for each

temperature setting of interest. Altern ately, if the RPM based Fan Speed Control Algorithm is not to be

used, then the user must program a drive setting for each temperature setting of interest.

If the measured temperature on the External Diode channel meets or exceeds any of the temperature

thresholds for any of the channels, the fan output will be automatically set to the desired setting

corresponding to the exceeded temperature. In cases where multiple temperature channel thresholds

are exceeded, the highest fan drive setting will take precedence.

When the measured temperat ure drops to a point below a lower threshold minus the hysteresis value,

the fan output will be set to the corresponding lower set point.

The following sections show examples of how the Look Up Table is used and configured. Each Look

Up Table Example uses the Fan 1 Look Up Table Registers configured as shown in Table B.1.

B.1 Example #1

This example does not use the RPM based Fan Speed Control Algorithm. Instead, the Look Up Table

is configured to directly set a fan drive setting bas ed on the temperature of f our of its measured inputs.

The configuration is set as shown in Table B.2.

Once configured, the Look Up Table is loaded as shown in Table B.3. Table B.3 shows three

temperature configurations using the settings in Table B.3 and the final fan drive setting that the Look

Up Table will select.

Table B.1 Look Up Table Format

STEP TEMP 1 TEMP 2 TEMP 3 TEMP 4 LUT DRIVE

1LUT Temp 1

Setting 1 (52h) LUT Temp 2

Setting 1 (53h) LUT Temp 3

Setting 1 (54h) LUT Temp 4

Setting 1 (55h) LUT Drive

Setting 1 (51h)

2LUT Temp 1

Setting 2 (57h) LUT Temp 2

Setting 2 (58h) LUT Temp 3

Setting 2 (59h) LUT Temp 4

Setting 2 (5Ah) LUT Drive

Setting 2 (56h)

3LUT Temp 1

Setting 3 (5Ch) LUT Temp 2

Setting 3 (5Dh) LUT Temp 3

Setting 3 (5Eh) LUT Temp 4

Setting 3 (5Fh) LUT Drive

Setting 3 (5Bh)

4LUT Temp 1

Setting 4 (61h) LUT Temp 2

Setting 4 (62h) LUT Temp 3

Setting 4 (63h) LUT Temp 4

Setting 4 (64h) LUT Drive

Setting 4 (60h)

5LUT Temp 1

Setting 5 (66h) LUT Temp 2

Setting 5 (67h) LUT Temp 3

Setting 5 (68h) LUT Temp 4

Setting 5 (69h) LUT Drive

Setting 5 (65h)

6LUT Temp 1

Setting 6 (6Bh) LUT Temp 2

Setting 6 (6Ch) LUT Temp 3

Setting 6 (6Dh) LUT Temp 4

Setting 6 (6Eh) LUT Drive

Setting 6 (6Ah)

7LUT Temp 1

Setting 7 (70h) LUT Temp 2

Setting 7 (71h) LUT Temp 3

Setting 7 (72h) LUT Temp 4

Setting 7 (73h) LUT Drive

Setting 7 (6Fh)

8LUT Temp 1

Setting 8 (75h) LUT Temp 2

Setting 8 (76h) LUT Temp 3

Setting 8 (77h) LUT Temp 4

Setting 8 (78h) LUT Drive

Setting 8 (74h)

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

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B.1.1 LUT Configuration Bit Description

Bit 7 - USE_DTS_F1 = ‘0b’ tells the circuitry that the Forced Temperature 1 registe r data is not in DTS

format.

Bit 6 - USE_DTS_F2 = ‘0b’ tells the circuitry that the Forced Temperature 2 registe r data is not in DTS

format.

Bit 5 - LUT_LOCK = ‘1b’ tells the circuitry that the LUT is programmed and is active. This bit must be

set for the LUT to function.

Bit 4 - TACH / DRIVE = ‘1b’ tells the Look Up Table that the FSC algorithm is not used and that the

LUT target values will be PWM drive settings instead of TACH Target settings.

Bits 3- 2 - TEMP3_CFG = ‘00b’ tells the LUT to re ference the External Diode 3 data instead of Forced

Temperature 1 data or the TRIP_SET / VIN4 voltage data. This is the default setting.

Bit 0 - TEMP4_CFG = ‘0b’ tells the LUT to reference the Internal Diode data instead of Forced

Temperature 2 data or the External Diode 4 temperature data. This is the default setting.

Note: The values shown in Table B.3 are example settings. All the cells in the look-up table are

programmable via SMBus.

Table B.2 Look Up Table Exam pl e # 1 Configuration

ADDR REGISTER B7 B6 B5 B4 B3 B2 B1 B0 SETTING

50h LUT 1

Configuration

USE_D

TS_F1 USE_D

TS_F2 LUT_L

OCK T ACH /

DRIVE TEMP3_CFG

[1:0] TEMP4_CFG

[1:0] C0h

0 01100 00

Table B.3 Fan Speed Control Table Example #1

FAN

SPEED

STEP #

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

EXTERNAL

DIODE 3

TEMPERATURE

(SKIN)

INTERNAL DIODE

TEMPERATURE

(AMBIENT) FAN DRIVE

SETTINGS

135

oC60

oC30

oC40

oC0%

240

oC70

oC35

oC45

oC30%

350

oC75

oC40

oC50

oC40%

460

oC80

oC45

oC55

oC50%

570

oC85

oC50

oC60

oC60%

680

oC90

oC55

oC65

oC70%

790

oC95

oC60

oC70

oC80%

8100

oC100

oC65

oC75

oC 100%

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B.2 Example #2

This example uses the RPM based Fan Speed Control Algorithm. The Spin Level (used by the Spin

Up Routine) should be changed to 50% drive for a total Spin Time of 1 second. For all other RPM

configuration settings, the default conditions are used.

For control inputs, it uses the External Diode 1 channel normally, a thermistor input on the External

Diode 2 channel, the internal diode channel, and a Pushed Temperature that represents the MCU

temperature in standard format. The configuration is set as shown in Table B.5 while Table B.6 shows

how the table is loaded.

Note that when using Thermistor data, the VIN2_INV bit should be set. The circuitry will automatically

subtract the measured thermistor vo ltage from a quantity of FFh (effectively inverting it). Th erefore, the

Look Up Table is loaded with ascending voltage thresholds with respect to the drive settings.

Additionally, the reading register will show this same value (subtracted from FFh).

Table B.4 Fan Speed Determination for Example #1 (using settin gs in Table B.3)

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

EXTERNAL DIODE

3 TEMPERATURE

(SKIN)

INTERNAL DIODE

TEMPERATURE

(AMBIENT) FAN DRIVE

SETTING RESULT

Example 1: 82°C 82°C 48°C 58°C 70% (CPU temp

requires highe st drive)

Example 2: 82C° 97°C 62°C 58°C 80% (GPU and Skin

require highest drive)

Example 3: 82°C 97°C 62°C 75°C 100% (Internal temp

requires highe st drive)

Table B.5 Look Up Table Exam pl e # 2 Configuration

ADDR REGISTER B7 B6 B5 B4 B3 B2 B1 B0 SETTING

22h Configuration

3-VIN4_I

NV VIN3_E

NVIN3_I

NV VIN2_

EN VIN2_I

NV VIN1_

EN VIN1_I

NV 0Ch

- 0 0 0 1100

42h Fan 1

Configuration

EN_

ALGO RANGE[1:0] EDGES[1:0] UPDATE[2:0] ABh

10101011

46h Fan 1 Spin

Configuration

DRIVE_FAIL_CNT

1 [1:0] NOKICK

1SPIN_LVL[2:0] SPINUP_TIME

[1:0] 0Ah

00001010

50h LUT 1

Configuration

USE_D

TS_F1 USE_D

TS_F2 LUT_LO

CK TACH /

DRIVE TEMP3_CFG

[1:0] TEMP4_CFG

[1:0] 28h

00101000

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B.2.1 Configuration 3 Bit Description

Bit 6 - VIN4_INV = ‘0b’ tells the circuitry that the VIN4 voltage is not inverted and will be asscending

(i.e. a value of 7Fh will represent a larger value than a value of 30h) If used by the LUT, no special

processing needs to be done. This is the default setting.

Bit 5 - VIN3_EN = ‘0b’ tells the circuitry that the VIN3 voltage is not measured. The External Diode 3

pins will measure the External Diode 3 temperature. This is the default setting.

Bit 4 - VIN3_INV = ‘0b’ tells the circuitry that the VIN3 voltage is not inverted. This bit is ignored

because VIN3_EN = ‘0b’. This is the default setting

Bit 3 - VIN2_EN = ‘1b’ tells the circuitry that the External Diode 2 pins (DP2 and DN2) will measure

the VIN2 voltage and will not measure the External Diod e 2 temperature. Th is voltage will au to ma tica lly

be used by the LUT.

Bit 2 - VIN2_INV = ‘1b’ tells the circuitry that the VIN2 voltage should be inverted. This means that

prior to any limit comparasions (via the high / low limits or the LUT), the measured value will be

subtracted from a value of FFh.

Bit 1 - VIN1_EN = ‘0b’ tells the circuitry that the VIN1 voltage is not measrued. The External Diode 1

pins (DP1 and DN1) will measure the External Diode 1 temperatu re and will be used by the LUT. This

is the default setting.

Bit 0 - VIN1_INV = ‘0b’ tells the circuitry that the VIN1 voltage is not inverted. This bit is ignored

because VIN1_EN = ‘0b’. This is the defautl setting.

B.2.2 Fan Configuration 1 Bit Description

Bit 7 - EN-ALGO = ‘1b’ tells the circuitry that the FSC alogrithm is active.

Bits 6 - 5 - RANGE[1:0] = ‘01b’ tells the FSC that the expected minimum RPM is 1000. This is the

defautl setting.

Bits 4-3 - EDGES[1:0] = ‘01b’ tells the FSC that the fan is a 2-pole fan generating tach edges per

rotation. This is the defautl setting.

Bits 2 - 0 - UPDATE[2:0] = ‘011b’ tells the FSC to update th e fan drive every 400ms. This is the default

setting.

B.2.3 Fan Spin Up Configuration Bit Description

Bits 7-6 - DRIVE_FAIL_CNT[1:0] = ‘00b’ tells the circuitry that the drive fail detection circuitry is not

enabled. This is the default setting.

Bit 5 - NOKICK = ‘0b’ tells the circuitry that if than Spin Up Routine is invoked, it will drive to 100%

duty cycle for 25% of the spin up time. This is the default setting.

Bits 4-2 - SPIN_LVL[2:0] = ‘010b’ tells the circuitry that if the Spin Up Routine is invoked, it sho uld run

at 40% drive.

Bits 1-0 - SPINUP_TIME[1:0] = ‘10b’ tells the circuitry that if the Spin Up Routine is invoked, it will run

at 100% duty cycle for 250ms and at 40% duty cycle for 750ms for a total spin up time of 1s.

B.2.4 LUT Configuration - Bit Description

7 - USE_DTS_F1 = ‘0b’ tells the circuitry that the data in the Pushed Temperature 1 register is in

normal format.

Bit 6 - USE_DTS_F2 = ‘0b’ tells the circuitry that the data in the Pushed Temperature 2 register is in

normal format.

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Bit 5 - LUT_LOCK = ‘1b’ tells the circuitry that the LUT is programmed and is active. This bit must be

set for the LUT to function.

Bit 4 -TACH / DRIVE = ‘0b’ tells the LUT circuitry that the FSC algorithm is active and that the LUT

values are TACH Target settings. This is the default setting.

Bits 3-2 - TEMP3_CFG = ‘10’b tells the Look Up Table to reference the Forced Temperature 1 data

instead of the External Diode 3 data or the TRIP_SET / VIN4 data.

Bits 1- 0- TEMP4_CFG = ‘00b’ tells the Look Up Table to reference the Internal Temperature data

instead of the External Diode 4 data or the Forced Temperature 2 data.

Note: The values shown in Table B.6 are example settings. All the cells in the look-up table are

programmable via SMBus.

Table B.6 Fan Speed Control Table Example #2

FAN

SPEED

STEP #

EXTERNAL DIODE

1 TE MPERATURE

(CPU)

THERMISTOR 2

VOLTAGE

READING

PUSHED

TEMPERATURE

SETTING

INTERNAL DIODE

TEMPERATURE

(AMBIENT) TACH

TARGET

135

oC156.25mV

(45°C) 30oC40

oCEFh

(1028 RPM)

240

oC178.125mV

(50°C) 35oC45

oCA3h

(1508 RPM)

350

oC203.125mV

(55°C) 40oC50

oC7Ah

(2014 RPM)

460

oC 228.125mV

(60°C) 45oC55

oC62h

(2508 RPM)

570

oC253.125mV

(65°C) 50oC60

oC52h

(2997 RPM)

680

oC278.125mV

(70°C) 55oC65

oC3Dh

(4029 RPM)

790

oC306.25mV

(75°C) 60oC70

oC31h

(5016 RPM)

8100

oC334.375mV

(80°C) 65oC75

oC29h

(5994 RPM)

Table B.7 Fan Speed Determination for Example #2 (using settin gs in Table B.6)

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

THERMISTOR 2

VOLTAGE

READING PUSHED

TEMPERATURE

INTERNAL DIODE

TEMPERATURE

(AMBIENT) FAN DRIVE

SETTING RESULT

Example 1: 75°C 140.375mV 48°C 58°C 52h (2997 RPM) -

CPU requires highest

target

Example 2: 75°C 310mV 58°C 58°C 31h (5016 RPM)

Thermistor requires

highest target

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B.3 Example #3

This example uses the RPM based Fan Speed Control Algorithm. The Spin Level (used by the Spin

Up Routine) should be changed to 50% drive for a total Spin Time of 1 second. For all other RPM

configuration settings, the default conditions are used.

For control inputs, it uses the External Diode 1 channel normally, the External Diode 2 channel

normally, and both Pushed Temperature registers in DTS format. The configuration is set as shown in

Table B.8 while Table B.9 shows how the table is loaded.

Note that when using DTS data, the USE_DTS_F1 and / or USE_DTS_F2 bits should be set. The

Pushed Temperature Registers are loaded with the normal DTS values as received by the processor.

When the DTS value is used by the Loo k Up Table, the value that is stored in the Pushed Temp erature

This resultant value is then compared against the Look Up Table thresholds normally. When

programming the Look Up Table, it is necessary to take this translation into account else incorrect

settings may be selected.

B.3.1 Fan Configuration 1 Bit Description

Bit 7 - EN-ALGO = ‘1b’ tells the circuitry that the FSC alogrithm is active.

Bits 6 - 5 - RANGE[1:0] = ‘01b’ tells the FSC that the expected minimum RPM is 1000. This is the

defautl setting.

Bits 4-3 - EDGES[1:0] = ‘01b’ tells the FSC that the fan is a 2-pole fan generating tach edges per

rotation. This is the defautl setting.

Example 3: 75°C 235.125mV 62°C 58°C 31h (5016 RPM)

Pushed Temperature

requires highest

target

Table B.8 Look Up Table Exam pl e # 3 Configuration

ADDR REGISTER B7 B6 B5 B4 B3 B2 B1 B0 SETTING

42h Fan 1

Configuration

EN_

ALGO RANGE[1:0] EDGES[1:0] UPDATE[2:0] ABh

10101011

46h Fan 1 Spin

Configuration

DRIVE_FAIL_CNT

1 [1:0] NOKICK

1SPIN_LVL[2:0] SPINUP_TIME

[1:0] 0Ah

00001010

50h LUT 1

Configuration

USE_D

TS_F1 USE_D

TS_F2 LUT_LO

CK TACH /

DRIVE TEMP3_CFG

[1:0] TEMP4_CFG

[1:0] EAh

11101010

Table B.7 Fan Speed Determination for Example #2 (using settin gs in Table B.6)

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

THERMISTOR 2

VOLTAGE

READING PUSHED

TEMPERATURE

INTERNAL DIODE

TEMPERATURE

(AMBIENT) FAN DRIVE

SETTING RESULT

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Bits 2 - 0 - UPDATE[2:0] = ‘011b’ tells the FSC to update th e fan drive every 400ms. This is the default

setting.

B.3.2 Fan Spin Up Configuration Bit Description

Bits 7-6 - DRIVE_FAIL_CNT[1:0] = ‘00b’ tells the circuitry that the drive fail detection circuitry is not

enabled. This is the default setting.

Bit 5 - NOKICK = ‘0b’ tells the circuitry that if than Spin Up Routine is invoked, it will drive to 100%

duty cycle for 25% of the spin up time. This is the default setting.

Bits 4-2 - SPIN_LVL[2:0] = ‘010b’ tells the circuitry that if the Spin Up Routine is invoked, it sho uld run

at 40% drive.

Bits 1-0 - SPINUP_TIME[1:0] = ‘10b’ tells the circuitry that if the Spin Up Routine is invoked, it will run

at 100% duty cycle for 250ms and at 40% duty cycle for 750ms for a total spin up time of 1s.

B.3.3 LUT Configuration - Bit Description

Bit 7 - USE_DTS_F1 = ‘1b’ tells the circuitry that the data in the Pushed Temperature 1 register is in

DTS format which means that the value in the register is equal to 100C - CPU Temp.

Bit 6 - USE_DTS_F2 = ‘1b’ tells the circuitry that the data in the Pushed Temperature 2 register is in

DTS format which means that the value in the register is equal to 100°C - CPU temp.

Bit 5 - LUT_LOCK = ‘1b’ tells the circuitry that the LUT is programmed and is active. This bit must be

set for the LUT to function.

Bit 4 -TACH / DRIVE = ‘0b’ tells the LUT circuitry that the FSC algorithm is active and that the LUT

values are TACH Target settings. This is the default setting.

Bits 3-2 - TEMP3_CFG = ‘10’b tells the Look Up Table to reference the Forced Temperature 1 data

instead of the External Diode 3 data or the TRIP_SET / VIN4 data.

Bits 1- 0- TEMP4_CFG = ‘10b’ tells the Look Up Table to reference the Forced Temeprature 2 data

instead of the Internal Diode data or the External Diode 4 data.

Table B.9 Fan Speed Control Table Example #3

FAN

SPEED

STEP #

EXTERNAL DIODE

1 TE MPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

PUSHED

TEMPERATURE

SETTING (DTS1)

PUSHED

TEMPERATURE

SETTING (DTS2) TACH

TARGET

135

oC65

oC50

oC40

oCEFh

(1028 RPM)

240

oC75

oC55

oC45

oCA3h

(1508 RPM)

350

oC85

oC60

oC50

oC7Ah

(2014 RPM)

460

oC90

oC65

oC55

oC62h

(2508 RPM)

570

oC95

oC70

oC60

oC52h

(2997 RPM)

680

oC 100oC75

oC65

oC3Dh

(4029 RPM)

Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

Datasheet

SMSC EMC2106 105 Revision 1.78 (04-21-09)

DATASHEET

Note: The values shown in Table B.9 are example settings. All the cells in the look-up table are

programmable via SMBus.

790

oC 105oC80

oC80

oC31h

(5016 RPM)

8100

oC110

oC85

oC 100oC29h

(5994 RPM)

Table B.10 Fan Speed Determination for Example #3 (using settings in Table B.9)

EXTERNAL

DIODE 1

TEMPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

PUSHED

TEMPERATURE

(DTS1)

PUSHED

TEMPERATURE

(DTS2) FAN DRIVE

SETTING RESULT

Example 1: 75°C 75°C 35°C

(translated as 65°C) 50°C

(translated as 50°C) 52h (2997 RPM) -

CPU requires highest

target

Example 2: 75°C 90°C 15°C

(translated as

85°C)

20°C

(translated as 80°C) 29h (5994 RPM) -

DTS1 requires

highest target

Example 3: 75°C 97.25°C 30°C

(translated as 70°C)

23°C

(translated as

77°C)

3Dh (40296 RPM) -

DTS2 requires

highest target

Table B.9 Fan Speed Control Table Example #3 (con tinued)

FAN

SPEED

STEP #

EXTERNAL DIODE

1 TE MPERATURE

(CPU)

EXTERNAL

DIODE 2

TEMPERATURE

(GPU)

PUSHED

TEMPERATURE

SETTING (DTS1)

PUSHED

TEMPERATURE

SETTING (DTS2) TACH

TARGET

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DATASHEET

Chapter 8 Revision History

Table 8.1 Customer Revision History

REVISION LEVEL & DATE SECTION/FIGURE/ENTRY CORRECTION

Rev. 1.78 (04-21-09)

Table 3.2, "Electrical

Specifications" Added electrical specs for SMbus delay and time

to first conversion

Section 7.2, "Package

Markings" Added figures for package markings

Rev. 1.77 (03-16-09) RPM Appe ndix Removed this appendix to consolidate information

in application note

Rev. 1.76 (03-11-09) Section 6.34, "TACH

Reading Registers" Added reference to application note AN17.4

Rev. 1.75 (03-06-09) Appendix B "Look Up Table

Operation" Updated entire section - examples were incorrect

for RPM values and fleshed out bit descriptions

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