SMSC USB2502 DATASHEET Revision 2.3 (08-27-07)
Datasheet
PRODUCT FEATURES
USB2502
2-Port USB 2.0 Hub
Controller
Integrated USB 2.0 Compatible 2-Port Hub
— High-Speed (480Mbits/s), Full-Speed (12Mbits/s) and
Low-Speed (1.5Mbits/s) compatible
— Full power management with ganged power control
— Detects Bus-Power/Self-Power source and changes
mode automatically
Complete USB Specification 2.0 Compatibility
— Includes USB 2.0 Transceivers
VID/PID/DID, and Port Configuration for Hub via:
— Single Serial I2C EEPROM
— SMBus Slave Port
Default VID/PID/DID, allows functionality when
configuration EEPROM is absent
Hardware Strapping options allow for configuration
without an external EEPROM or SMBus Host
On-Board 24MHz Crystal Driver Circuit or 24 MHz
external clock driver
Internal PLL for 480MHz USB 2.0 Sampling
Internal 1.8V Linear Voltage Regulator
Integrated USB termination and Pull-up/Pull-down
resistors
Internal Short Circuit protection of USB differential
signal pins
Basic single-color LED support
1.8 Volt Low Power Core Operation
3.3 Volt I/O with 5V Input Tolerance
36 Pin QFN or 48 Pin TQFP lead-free RoHS
compliant package
ORDER NUMBERS:
USB2502-AEZG FOR 36 PIN LEAD-FREE ROHS COMPLIANT QFN PACKAGE; USB2502-HT FOR 48 PIN LEAD-
FREE ROHS COMPLIANT TQFP PACKAGE
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 2 SMSC USB2502
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2007 SMSC or its subsidiaries. All rights reserved.
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 in accuracies. 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 IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, 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 ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POS SIBILITY OF SUCH DAMAGES.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 3 Revision 2.3 (08-27-07)
DATASHEET
Table of Contents
Chapter 1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 OEM Selectable Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter 2 Pin Table 2-Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 3 Pin Configuration 2-Port Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 4 2-Port Hub Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Chapter 5 Functional Block Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1 2-Port Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.1 Hub Configuration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.2 VBus Detect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2 EEPROM Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2.1 I2C EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2.2 In-Circuit EEPROM Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2.3 EEPROM DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.3 SMBus Slave Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.1 Bus Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.2 Invalid Protocol Response Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.3 General Call Address Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.4 Slave Device Time-Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.5 Stretching the SCLK Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.6 SMBus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.7 Bus Reset Sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.8 SMBus Alert Response Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.9 Internal SMBus Memory Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.4 Default Configuration Option: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.5 Default Strapping Options: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.6 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.6.1 External Hardware RESET_N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.6.2 USB Bus Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Chapter 6 XNOR Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter 7 DC Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.1 Maximum Guaranteed Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.2 Recommended Operating Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter 8 AC Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1 Oscillator/Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1.1 SMBus Interface:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1.2 I2C EEPROM: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1.3 USB 2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Chapter 9 Package Outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 4 SMSC USB2502
DATASHEET
List of Tables
Table 2.1 2-Port Pin Table for 36-QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 2.2 2-Port Pin Table for 48-TQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 4.1 2-Port Hub Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 4.2 SMBus or EEPROM Interface Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 4.3 Miscellaneous Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 4.4 Power, Ground, and No Connect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 4.5 Buffer Type Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 5.1 User-Defined Descriptor Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 5.2 SMBus Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 5.3 SMBus Read Byte Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 5.4 SMBus Slave Interface Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 5.5 Reset_N Timing for Default/Strap Option Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 5.6 Reset_N Timing for EEPROM Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 5.7 Reset_N Timing for SMBus Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 7.1 DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 9.1 48 Pin TQFP Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 5 Revision 2.3 (08-27-07)
DATASHEET
List of Figures
Figure 3.1 2-Port 36-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 3.2 2-Port 48-Pin TQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 4.1 2-Port Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5.1 LED Strapping Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 5.2 Reset_N Timing for Default/Strap Option Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 5.3 Reset_N Timing for EEPROM Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 5.4 Reset_N Timing for SMBus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 9.1 36 Pin QFN Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 9.2 48 Pin TQFP Package Outline (7x7x1.4 mm body, 2mm Footprint) . . . . . . . . . . . . . . . . . . . 44
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 6 SMSC USB2502
DATASHEET
Chapter 1 General Description
The SMSC 2-Port Hub is fully compliant with the USB 2.0 Specification and will attach to a USB host
as a Full-Speed Hub or as a Full-/High-Speed Hub. The 2-Port Hub supports Low-Speed, Full-Speed,
and High-Speed (if operating as a High-Speed Hub) downstream devices on all of the enabled
downstream ports.
The Hub works with an external USB power distribution switch device to control VBUS switching to
downstream ports, and to limit current and sense over-current conditions.
All required resisto rs on the USB ports are integrated into the H ub. This includes all series termina tion
resistors on D+ and D– pins and all required pull-down and pull-up resistors on D+ and D– pins. The
over-current sense inputs for the downstream facing ports have internal pull-up resistors.
Throughout this document the upstream facing port of the hub will be referred to as th e upstream port,
and the downstream facing ports will be called the downstream ports.
1.1 OEM Selectable Features
A default configuration is available in the USB2502 following a reset. This configuration may be
sufficient for some applications. Strapping option pins make it possible to modify a limited sub-set of
the configuration options.
The USB2502 may also be configured by an external EEPROM or a microcontroller. When using the
microcontroller interface, the Hub appears as an SMBus slave device. If the Hub is pin-strapped for
external EEPROM configuration but no external EEPROM is present, then a value of ‘0’ will be written
to all configuration data bit fields (the hub will attach to the host with all ‘0’ values).
The 2-Port Hub supports several OEM selectable features:
Operation as a Self-Powered USB Hub or as a Bus-Powered USB Hub.
Operation as a Dynamic-Powered Hub (Hub operates as a Bus-Powered device if a local power
source is not available and switches to Self-Powered operation when a local power source is
available).
Optional OEM configuration via I2C EEPROM or via the industry standard SMBus interface from
an external SMBus Host.
Compound device support (port is permanen tl y hardw ired to a downs tream USB perip heral device ).
Hardware strapping options enable configuration of the following features.
Non-Removable Ports
Port Power Polarity (active high or active low logic)
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 7 Revision 2.3 (08-27-07)
DATASHEET
Chapter 2 Pin Table 2-Port
Table 2.1 2-Port Pin Table for 36-QFN
UPSTREAM USB 2.0 INTERFACE (3 PINS)
USBDP0 USBDN0 VBUS_DET
2-PORT USB 2.0 INTERFACE (10 PINS)
USBDP1 USBDN1 USBDP2 USBDN2
GR1/
NON_REM0 GR2/
NON_REM1 PRTPWR_POL RBIAS
PRTPWR OCS_N
SERIAL PORT INTERFACE (3 PINS)
SDA/SMBDATA SCL/SMBCLK/
CFG_SEL0 CFG_SEL1
MISC (7 PINS)
XTAL1/CLKIN XTAL2 RESET_N SELF_PWR
ATEST/
REG_EN CLKIN_EN TEST
POWER, GROUND (13 PINS)
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 8 SMSC USB2502
DATASHEET
Table 2.2 2-Port Pin Table for 48-TQFP
UPSTREAM USB 2.0 INTERFACE (3 PINS)
USBDP0 USBDN0 VBUS_DET
2-PORT USB 2.0 INTERFACE (10 PINS)
USBDP1 USBDN1 USBDP2 USBDN2
GR1/
NON_REM0 GR2/
NON_REM1 PRTPWR_POL RBIAS
PRTPWR OCS_N
SERIAL PORT INTERFACE (3 PINS)
SDA/SMBDATA SCL/SMBCLK
CFG_SEL0 CFG_SEL1
MISC (7 PINS)
XTAL1/CLKIN XTAL2 RESET_N SELF_PWR
ATEST/
REG_EN CLKIN_EN TEST
POWER, GROUND AND NO CONNECT (25 PINS)
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 9 Revision 2.3 (08-27-07)
DATASHEET
Chapter 3 Pin Configuration 2-Port Hub
Figure 3.1 2-Port 36-Pin QFN
Thermal Slug
(must be connected to VSS)
SMSC
USB2502
(Top View QFN-36)
Indicates pins on the bottom of the device.
VDDA33 1
USBDP0 2
USBDN0 3
VSS 4
USBDN1 5
USBDP1 6
VDDA33 7
USBDP2 8
USBDN2 9
18 VDD18
17 VSS
16 SELF_PWR
15 OCS_N
14 PRTPWR
13 PRTPWR_POL
12 GR2/NON_REM1
11 GR1/NON_REM0
10 VSS
VDD33CR 28
VSS 29
XTAL1/CLKIN 31
VDDA18PLL 32
VDDA33PLL 33
VSS 36
RBIAS 35
ATEST/REG_EN 34
XTAL2 30
26 VSS
25 VBUS_DET
24 RESET_N
23 TEST
22 CLKIN_EN
21 CFG_SEL1
20 SCL/SMBCLK/CFG_SEL0
19 SDA/SMBDATA
27 VDD18
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 10 SMSC USB2502
DATASHEET
Figure 3.2 2-Port 48-Pin TQFP
9''&5
966
;7$/
;7$/&/.,1
9''$3//
9''$3//
9''
966
*5121B5(0
*5121B5(0
6(/)B3:5
3573:5B32/
3573:5
9''$
$7(675(*B(1
5%,$6
966
2&6B1
86%'3
86%'1
966
966
86%'1
86%'3
9''$
9''$
86%'3
86%'1
966






1&
1&
9''
966
966
9%86B'(7
5(6(7
7(67
&/.,1B(1
&)*B6(/
6&/60%&/.&)*B6(/
6'$60%'$7$
1&
1&
1&
1&
9''&5
966
9''$3//
86%
74)3
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 11 Revision 2.3 (08-27-07)
DATASHEET
Chapter 4 2-Port Hub Block Diagram
Figure 4.1 2-Port Block Diagram
Table 4.1 2-Port Hub Pin Descriptions
NAME SYMBOL TYPE FUNCTION
UPSTREAM USB 2.0 INTERFACE
USB Bus Data USBDN0
USBDP0 IO-U These pins connect to the upstream USB bus data signals.
Detect Upstream
VBUS Power VBUS_DET I/O8 Detects state of Upstream VBUS power. The SMSC Hub
monitors VBUS_DET to determine when to assert the
internal D+ pull-up resistor (signalling a connect event).
When designing a detachable hub, this pin must be
connected to the VBUS power pin of the USB port that is
upstream of the hub. (Use of a weak pull-down resistor is
recommended.)
For self-powered applications with a permanently attached
host, this pin must be pulled-up to either 3.3V or 5.0V
(typically VDD33).
8SVWUHDP
VBUS
3.3V
Upstream
PHY
Upstream
USB Data
Repeater Controller
SIE
Serial
Interface
PLL
24 MHz
Crystal To EEPROM or
SMBus Master
Routing Logic
SCKSD
Port
Controller
Downstream PHY #1
OC Sense
Switch Driver
LED Driver
Strapping Options
Downstream PHY #2
Downstream
USB Data OC
Sense Switch/LED
Driver/optís Downstream
USB Data
Bus-Power
'HWHFW
1.8V
Transaction Translator
1.8V Reg
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 12 SMSC USB2502
DATASHEET
2-PORT USB 2.0 HUB INTERFACE
High-Speed USB
Data USBDN[2:1]
USBDP[2:1] IO-U These pins connect to the downstream USB peripheral
devices attached to the Hub’s ports.
USB Power
Enable PRTPWR O8 Enables power to USB peripheral devices (downstream).
The active signal level of the PRTPWR pin is determined by
the Power Polarity Strapping function of the PRTPWR_POL
pin.
Port [2:1] Green
LED
&
Port Non-
Removable
strapping option.
GR[2:1]/
NON_REM[1:0] I/O8 Green indicator LED for ports 2 and 1. Will be active low
when LED support is enabled via EEPROM or SMBus.
If the hub is conf igured by th e internal def ault conf igurat ion,
these pins will be sampled at the rising edge of RESET_N
(see the applicable RESET_N timing table in Section 5.6.1)
to determine if ports [2:1] contain permanently attached
(non-removable) devices. Also, the active state of the LED’s
will be determined as follows:
NON_REM[1:0] = ‘00’, All ports are removable,
GR2 is active high,
GR1 is active high.
NON_REM1:0] = ‘01’, Port 1 is non-removable,
GR2 is active high,
GR1 is active low.
NON_REM[1:0] = ‘10’, Ports 1 & 2 are non-removable,
GR2 is active low,
GR1 is active high.
NON_REM[1:0] = ‘11’, Ports 1 & 2 are non-removable,
GR2 is active low,
GR1 is active low.
Port Power
Polarity strapping. PRTPWR_POL I/O8 Port Power Polarity strapping determination for the active
signal polarity of the PRTPWR pin.
While RESET_N is asserted, the logic state of this pin will
(though the use of internal combinatorial logic) determine
the active state of the PRTPWR pin in order to ensure that
downstream port power is not inadvertently enabled to
inactive ports during a hardware reset.
On the rising edge of RESET_N (see the applicable
RESET_N timing table in Section 5.6.1), t he logic value wil l
be latched internally, and will retain the active signal polarity
for the PRTPWR pin.
‘1’ = PRTPWR pin has an active ‘high’ polarity
‘0’ = PRTPWR pin has an active ‘low’ polarity
Over Current
Sense OCS_N IPU Input from external current monitor indicating an over-
current condition. {Note: Contains internal pull-up to 3.3V
supply}
USB Transceiver
Bias RBIAS I-R A 12.0kΩ (+/− 1%) resistor is attached from ground to this
pin to set the transceiver’s internal bias settings.
Table 4.1 2-Port Hub Pin Descriptions (continued)
NAME SYMBOL TYPE FUNCTION
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 13 Revision 2.3 (08-27-07)
DATASHEET
SERIAL PORT INTERFACE
Serial Data/SMB
Data SDA/SMBDATA IOSD12 (Serial Data)/(SMB Data) signal.
Serial Clock/SMB
Clock
&
Config Select 0
SCL/SMBCLK/
CFG_SEL0 IOSD12 (Serial Clock)/(SMB Clock) signal. This multifunction pin is
read on the rising edge of RESET_N (see the applicable
RESET_N timing table in Section 5.6.1) and will determine
the hub configuration method as described in Table 4.2.
Configuration
Programming
Select
CFG_SEL1 I This pin is read on the rising edge of RESET_N (see the
applicable RESET_N timing table in Section 5.6.1) a nd will
determine the hub configuration method as described in
Table 4.2.
Table 4.2 SMBus or EEPROM Interface Behav ior
CFG_SEL1 CFG_SEL0 SMBus or EEPROM interface behavior.
00Reserved
0 1 Configured as an SMBus slave for externa l download of user-
defined descriptors. SMBus slave address is 0101100
1 0 Internal Default Configuration via strapping options.
1 1 2-wire (I2C) EEPROMS are supported,
Table 4.3 Miscellaneous Pins
NAME SYMBOL TYPE FUNCTION
Crystal
Input/External
Clock Input
XTAL1/
CLKIN ICLKx 24MHz crystal or external clock input.
This pin connects to either one te rminal of the crystal or
to an external 24MHz clock when a crystal is not used.
Crystal Output XTAL2 OCLKx 24MHz Crystal
This is the other terminal of the crystal, or left
unconnected when an external clock source is used to
drive XTAL1/CLKIN. It must not be used to drive any
external circuitry other than the crystal circuit.
Clock Input
Enable CLKIN_EN I Clock In Enable:
Low = XTAL1 and XTAL2 pins configured for use with
external crystal
High = XTAL1 pin configured as CLKIN, and must be
driven by an external CMOS clock.
RESET Input RESET_N IS This active low signal is used by the system to reset the
chip. The minimum active low pulse is 1us.
Self-Power /
Bus-Power
Detect
SELF_PWR I Detects availability of local self-power source.
Low = Self/local power source is NOT available (i.e., Hub
gets all power from Upstream USB VBus).
High = Self/local power source is available.
TEST Pin TEST IPD Used for testing the chip. User must treat as a no-
connect or connect to ground.
Table 4.1 2-Port Hub Pin Descriptions (continued)
NAME SYMBOL TYPE FUNCTION
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 14 SMSC USB2502
DATASHEET
Analog Test
&
Internal 1.8V
voltage
regulator
enable
ATEST/
REG_EN AIO This signal is used for testing the analog section of the
chip, and to ena ble or disable t he internal 1.8v regulato r.
This pin must be connected to VDDA33 to enable the
internal 1.8V regulator, or to VSS to disable the internal
regulator.
When the internal regulator is enabled, the 1.8V power
pins must be left unconnected, except for the required
bypass capacitors.When the PHY is in test mode, the
internal regulator is disabled and the ATEST pin
functions as a test pin.
Table 4.4 Power, Ground, and No Connect
NAME SYMBOL TYPE FUNCTION
VDDCORE3P3 VDD33CR +3.3V I/O Power.
If the internal core 1.8V regulator is enabled, then this pin
acts as the regulator input
VDD1P8 VDD18 +1.8V core power.
If the internal regulator is enabled, then VDD18 pin 27
must have a 4.7μF (or greater) ±20% (ESR <0.1Ω)
capacitor to VSS
VDDAPLL3P3 VDDA33PLL +3.3V Filtered analog power for the internal PLL
If the internal PLL 1.8V regulator is enabled, then this pin
acts as the regulator input
VDDAPLL1P8 VDDA18PLL +1.8V Filtered analog power for internal PLL.
If the internal regulator is enabled, then this pin must
have a 4.7μF (or greater) ±20% (ESR <0.1Ω) capacitor
to VSS
VDDA3P3 VDDA33 +3.3V Filtered analog power.
VSS VSS Ground.
Table 4.5 Buffer Type Descriptions
BUFFER DESCRIPTION
IInput.
IPD Input, with a weak Internal pull-down.
IPU Input, with a weak Internal pull-up.
IS Input with Schmitt trigger.
I/O8 Input/Output 8mA
O8 Output 8mA
Table 4.3 Miscellaneous Pins (continued)
NAME SYMBOL TYPE FUNCTION
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 15 Revision 2.3 (08-27-07)
DATASHEET
IOSD12 Open drain….12mA sink with Sch mitt t rigge r, and must meet I 2C-Bus Specification Version 2.1
requirements.
ICLKx XTAL Clock Input
OCLKx XTAL Clock Output
I-R RBIAS
IO-U Defined in USB Specification.
Note: Meets USB 1.1 requirements when operat ing as a 1.1-compliant device a nd meets USB
2.0 requirements when operating as a 2.0-compliant device.
AIO Analog Input/output. Per PHY test requirements.
Table 4.5 Buffer Type Descriptions (continued)
BUFFER DESCRIPTION
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 16 SMSC USB2502
DATASHEET
Chapter 5 Functional Block Description
5.1 2-Port Hub
SMSC’s USB 2.0 2-Port Hub is fully specification compliant to the Universal Serial Bus Specification
Revision 2.0 April 27,2000 (12/7/2000 and 5/28/2002 Errata). Please reference Chapter 11 (Hub
Specification) for general details regarding Hub operation and functionality.
For performance reasons, the 2-Port Hub provides 1 Transaction Translator (TT) per port (defined as
Multi-TT configuration), divided into 4 non-periodic buffers per TT.
5.1.1 Hub Configuration Options
The SMSC Hub supports a large number of features and must be configured in order to correctly
function when attached to a USB host controller. There are three principal ways to configure the hub:
SMBus, EEPROM, or by internal default settings. In all cases, the configuration method will be
determined by the CFG_SEL1 and CFG_SEL0 pins immediately after RESET_N negation.
5.1.1.1 Vendor ID
Is a 16-bit value that uniquely identifies the Vendor of the user device (assigned by USB-Interface
Forum). This field is set by the OEM using either the SMBus or EEPROM interface options. When
using the internal default option, SMSC’s VID (see Table 5.1) will be reported.
5.1.1.2 Product ID
Is a 16-bit value that the Vendor can assign that uniquely identifies this particular product (assigned
by OEM). This field is set by the OEM using either the SMBus or EEPROM interface options. When
using the internal default option, SMSC’s PID designation of (see Table 5.1) will be reported.
5.1.1.3 Device ID
Is a 16-bit device release number in BCD format (assigned by OEM). This field is set by the OEM
using either the SMBus or EEPROM interface options. When using the internal default option, SMSC’s
DID designation of (see Table 5.1) will be reported.
5.1.1.4 Self-Powered/Bus-Powered
The Hub is either Self-Powered (draws less than 2mA of upstream bus power) or Bus-Powered
(limited to a 100mA maximum of upstream power prior to being configured by the host controller).
When configured as a Bus-Powered device, the SMSC Hub consumes less than 100mA of current
prior to being configured. After configuration, the Bus-Powered SMSC Hub (along with all associated
hub circuitry, any embedded devices if part of a compound device, and 100mA pe r externally available
downstream port) must consume no more than 500mA of upstream VBUS current. The current
consumption is system dependent, and the OEM must ensure that the USB 2.0 specifications are not
violated.
When configured as a Self-Powered device, <1mA of upstream VBUS current is consumed and all 7
ports are available, with each port being capable of sourcing 500mA of current.
This field is set by the OEM using either the SMBus or EEPROM interface options. When using the
internal default option, the SELF_PWR pin determines the Self-powered or Bus-powered status.
Please see the description under Dynamic Power for the self/bus power functionality when dynamic
power switching is enabled.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 17 Revision 2.3 (08-27-07)
DATASHEET
5.1.1.5 High-Speed Disable
Allows an OEM to force the Hub to configure as a Full-Speed device only (i.e. High-Speed not
available).
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.6 EOP Disable
During FS operation only, this permits the Hub to send EOP if no downstream traffic is detected at
EOF1. See Section 11.3.1 of the USB 2.0 Specification for additional details.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.7 Current Sensing
Selects current sensing as all ports ganged, or none.
This field can be set by the OEM using either the SMBus or EEPROM interface options.When using
the internal default option, the SELF_PWR pin determines if current sensing will be ganged, or none
(ganged if self-powered, none if bus-powered)
5.1.1.8 Compound Device
Allows the OEM to indicate that the Hub is part of a compound (see the USB Specification for
definition) device. The applicable port(s) must also be defined as having a “Non-Removable Device”.
This field is set by the OEM using either the SMBus or EEPROM interface options.
Note: When configured via strapping options, decl aring a port as non-removable automatically causes
the hub controller to report that it is part of a compound device.
5.1.1.9 Non-Removable Device
Informs the Host if one of the active ports has a permanent device t hat is undetachable from the Hub.
(Note: The device must provide its own descriptor data.)
This field is set by the OEM using either the SMBus or EEPROM interface options. When using the
internal default option, the NON_REM[1:0] pins will designate the appropriate ports as being non-
removable.
5.1.1.10 Self-Powered Port DISABLE
During Self-Powered operation, this selects the ports which will be permanently disabled, and are not
available to be e nabled or enumerated by a Host Controller. The disabled ports must be in decreasing
order starting with port 2.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.11 Bus-Powered Port DISABLE
During Bus-Powered operation, this selects the ports which will be permanently disabled, and are not
available to be enabled or enumerat ed by a Host Controller. The disabled ports must be in decreasing
order starting with port 2.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.12 Dynamic Power
Controls the ability of the 2-Port Hub to automatically change from Self-Powered operation to Bus-
Powered operation if the local power source is removed or is unavailable (and from Bus-Powered to
Self-Powered if the local power source is restored). {Note: If the local power source is available, the
2-port Hub will always switch to Self-Powered operation.}
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 18 SMSC USB2502
DATASHEET
When Dynamic Power switching is enabled, the Hub detects the availability of a local power source
by monitoring the external SELF_PWR pin. If the Hub detects a change in power source availability,
the Hub immediately disconnects and removes power from all downstream devices and disconnects
the upstream port. The Hub will then re-attach to the upstream port as either a Bus-Powered Hub (if
local-power in unavailable) or a Self-Powered Hub (if local power is available).
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.13 Over-Current Timer
The time delay (in 2ms increments) for an over-current condition to persist before it is reported to the
Host.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.14 Self-Powered Max Power
When in Self-Powered configuration, Sets value in 2mA increments.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.15 Bus-Powered Max Power
When in Bus-Powered configuration, Sets value in 2mA increments.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.16 Self-powered Hub Controller Current
When in Self-Powered configuration, Maximum current requirements of the Hub Controller in 2mA
increments.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.17 Bus-Powered Hub Controller Current
When in Bus-Powered configuration, Maximum current requirements of the Hub Controller in 2mA
increments.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.18 Power-On Timer
Time (in 2ms intervals) fr om the time power-on sequence begins on a po rt until power is good on that
port. System software uses this value to determine how long to wait before accessing a powered-on
port.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.19 Power Switching Polarity
The selection of active state “polarity” for the PRTPWR2 pin is made by a strapping option only.
5.1.2 VBus Detect
According to Section 7.2.1 of the USB 2.0 Specification, a downstream port can never provide power
to its D+ or D- pull-up resistors unless the upstream port’s VBUS is in the asserted (powered) state.
The VBUS_DET pin on the Hub monitors the state of the upstream VBUS signal and will not pull-up
the D+ or D- resistor if VBUS is not active. If VBUS goes from an active to an inactive state (Not
Powered), Hub will remove power from the D+ or D- pull-up resistor within 10 seconds.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 19 Revision 2.3 (08-27-07)
DATASHEET
5.2 EEPROM Interface
The SMSC Hub can be configured via a 2-wire (I2C) EEPROM. (Please see Table 4.1, "7-Port Hub
Pin Descriptions" for specific details on how to enable the I2C EEPROM option).
The Internal state-machine will, (when configured for EEPROM support) read the external EEPROM
for configuration data. The hub will then “attach” to the upstream USB host.
Please see Table 5.1 User-Defined Descriptor Data for a list of data fields available.
5.2.1 I2C EEPROM
The I2C EEPROM interface implements a subset of the I2C Master Specification (Please refer to the
Philips Semiconductor Standard I2C-Bus Specification for details on I2C bus p rotocols). The H ub’s I2C
EEPROM interface is designed to attach to a single “dedicated” I2C EEPROM, and it conforms to the
Standard-mode I2C Specification (100kbit/s transfer rate and 7-bit addressing) for protocol and
electrical compatibility.
Note: Extensions to the I2C Specification are not supported.
The Hub acts as the master and generates the serial clock SCL, controls the bus access (determines
which device acts as the transmitter and which device acts as the receiver), and ge nerates the START
and STOP conditions.
5.2.1.1 Implementation Characteristics
Please refer to the MicroChip 24AA00 DataSheet for Protocol and Programming specifics.
5.2.1.2 Pull-Up Resistor
The Circuit board desi gner is required to place external pull-up resi stors (10KΩ recommended) on the
SDA/SMBDATA & SCL/SMBCLK/CFG_SELO lines (per SMBus 1.0 Specification, and EEPROM
manufacturer guidelines) to Vcc in order to assure proper operation.
5.2.1.3 I2C EEPROM Slave Address
Slave address is 1010000.
Note: 10-bit addressing is NOT supported.
5.2.2 In-Circuit EEPROM Programming
The EEPROM can be programmed via ATE by pulling RESET_N low (which tri-states the Hub’s
EEPROM interface and allows an external source to program the EEPROM).
5.2.3 EEPROM DATA
Table 5.1 User-Defined Descriptor Data
FIELD
BYTE
MSB:
LSB SIZE
(BYTES)
DEFAULT
CFG
SELF
(HEX)
DEFAULT
CFG
BUS
(HEX) DESCRIPTION
VID 1:0 2 0424 0424 Vendor ID (assigned by USB-IF).
PID 3:2 2 2502 2502 Product ID (assigned by Manufacturer).
DID 5:4 2 0000 0000 Device ID (assigned by Manufacturer).
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 20 SMSC USB2502
DATASHEET
5.2.3.1 EEPROM Offset 1:0(h) - Vendor ID
5.2.3.2 EEPROM Offset 3:2(h) - Product ID
Config Data
Byte 1 6 1 88 0C Configuration data byte #1 for Hub options.
Config Data
Byte 2 7 1 90 90 Configuration data byte #2 for Hub options.
Non
Removable
Device
8 1 00 00 Defines the ports that contain attached
devices (this is used only when Hub is part of
a compound device).
Port Disable
Self-Powered 9 1 00 00 Selects the ports that will be permanently
disabled
Port Disable
Bus-Powered A 1 00 00 Selects the ports that will be permanently
disabled
Max Power
Self-Powered B 1 01 01 Max Current for th is conf igu rati on (exp ressed
in 2mA units).
Max Power
Bus-Powered C 1 64 64 Ma x Current f or th is configu rati on (exp re ssed
in 2mA units).
Hub Controller
Max Current
Self-Powered
D 1 01 01 Max Current (expressed in 2mA units).
Hub Controller
Max Current
Bus-Powered
E 1 64 64 Max Current (expressed in 2mA units).
Power-On
Time F 1 32 32 Time until power is stable.
BIT
NUMBER BIT NAME DESCRIPTION
15:8 VID_MSB Most Significant Byte of the Vendor ID.
7:0 VID_LSB Least Significant Byte of the Vendor ID.
BIT
NUMBER BIT NAME DESCRIPTION
15:8 PID_MSB Most Significant Byte of the Product ID.
7:0 PID_LSB Least Significant Byte of the Product ID.
Table 5.1 User-Defined Descriptor Data (continued)
FIELD
BYTE
MSB:
LSB SIZE
(BYTES)
DEFAULT
CFG
SELF
(HEX)
DEFAULT
CFG
BUS
(HEX) DESCRIPTION
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 21 Revision 2.3 (08-27-07)
DATASHEET
5.2.3.3 EEPROM Offset 5:4(h) - Device ID
5.2.3.4 EEPROM Offset 6(h) - CONFIG_BYTE_1
5.2.3.5 EEPROM Offset 7(h) - CONFIG_BYTE_2
BIT
NUMBER BIT NAME DESCRIPTION
15:8 DID_MSB Most Significant Byte of the Device ID.
7:0 DID_LSB Least Significant Byte of the Device ID.
BIT
NUMBER BIT NAME DESCRIPTION
7 SELF_BUS_PWR Self or Bus Power: Selects between Self- and Bus-Powered operation.
0 = Bus-Powered operation. (BUS Default)
1 = Self-Powered operation. (SELF Default)
Note: If Dynamic Power Switching is enabled, this bit is ignored and the
SELF_PWR pin is used to det ermine if the hub is operating from self or bu s
power.
6 Reserved Reserved
5 HS_DISABLE High Speed Disable: Disables the capability to attach as either a High/Full-
speed device, and force s attachment as Full-speed only i.e. (no High -Speed
support).
0 = High-/Full-Speed. (Default)
1 = Full-Speed-Only (High-Speed disabled!)
4 Reserved Reserved
3 EOP_DISABLE EOP Disable: Disables EOP generation at EOF1 when no downstream
directed traffic is in progress.
0 = EOP generation at EOF1 is enabled.
1 = EOP generation at EOF1 is disabled, (normal operation). (Default)
2:1 CURRENT_SNS Over Current Sense: Indicates whether current sensing is ganged.
00 = Ganged sensing (all ports together). (Default for self-power)
01 = Reserved
1x = Over current sensing not supported. (may be used with Bus-Powered
configurations only!, and is the default for bus-power)
0 Reserved Reserved
BIT
NUMBER BIT NAME DESCRIPTION
7 DYNAMIC Dynamic Power Enable: Controls the ability for the Hub to transition to Bus-
Powered operati on if the local power source is removed (can revert back to
Self-Power if local power source is restored).
0 = No Dynamic auto-switching.
1 = Dynamic Auto-switching capable.(Default)
6 Reserved Reserved
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 22 SMSC USB2502
DATASHEET
5.2.3.6 EEPROM Offset 8(h) - Non-Removable Device
5.2.3.7 EEPROM Offset 9(h) - Port Disable For Self Powered Operation
5.2.3.8 EEPROM Offset A(h) - Port Disable For Bus Powered Operation
5:4 OC_TIMER OverCurrent Timer: Over Current Timer delay.
00 = 0.1ms
01 = 2ms (Default)
10 = 4ms
11 = 6 m s
3 COMPOUND Compound Device: Designates if Hub is part of a compound device.
0 = No. (Default)
1 = Yes, Hub is part of a compound device.
2:0 Reserved Reserved.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 NR_DEVICE Non-Removable Device: Indicates which port(s) include non-removable devic-
es. ‘0’ = port is removable , ‘1’ = port is non-removable.
Bit 7:3= 0; Reserved
Bit 2= 1; Port 2 non-removable.
Bit 1= 1; Port 1 non removable.
Bit 0 is Reserved, always = ‘0’.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PORT_DIS_SP Port Disable Self-Powered: Disables 1 or more contiguous ports. ‘0’ = port
is available, ‘1’ = port is disabled.
Bit 7:3= 0; Reserved
Bit 2= 1; Port 2 is disabled.
Bit 1= 1; Port 1 is disabled.
Bit 0 is Reserved, always = ‘0’
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PORT_DIS_BP Port Disable Bus-Powered: Disables 1 or more contiguous ports. ‘0’ = port
is available, ‘1’ = port is disabled.
Bit 7:3= 0; Reserved
Bit 2= 1; Port 2 is disabled.
Bit 1= 1; Port 1 is disabled.
Bit 0 is Reserved, always = ‘0’
BIT
NUMBER BIT NAME DESCRIPTION
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 23 Revision 2.3 (08-27-07)
DATASHEET
5.2.3.9 EEPROM Offset B(h) - Max Power For Self Powered Operation
5.2.3.10 EEPROM Offset C(h) - Max Power For Bus Powered Operation
5.2.3.11 EEPROM Offset D(h) - Hub Controller Max Current For Self Powered Operation
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_SP Max Power Self _Powere d: Value in 2mA increments that the Hub consumes
from an upstream port (VBUS) when operating as a self-powered hub. This
value includes the hub silicon along with the combined power consumption
(from VBUS) of all associated circuitry on the board. This value also includes
the power consumption of a permanently attached peripheral if the hub is
configured as a compound device, and the embedded peripheral reports
0mA in its descriptors.
Note: The USB 2.0 Specification does not permit this value to exceed
100mA
A value of 50 (decimal) indicates 100mA.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_BP Max Power Bus_Powe re d: Value in 2mA increments that the Hub consumes
from an upstream port (VBUS) when operating a s a bus-powered hub. This
value includes the hub silicon along with the combined power consumption
(from VBUS) of all associated circuitry on the board. This value also includes
the power consumption of a permanently attached peripheral if the hub is
configured as a compound device, and the embedded peripheral reports
0mA in its descriptors.
A value of 50 (decimal) indicates 100mA.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 HC_MAX_C_SP Hub Controller Max Current Self-Powered: Value in 2mA increments that the
Hub consumes from an upstream port (VBUS) when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value does NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
Note: The USB 2.0 Specification does not permit this value to exceed
100mA
A value of 50 (decimal) indicates 100mA, which is the default value.
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 24 SMSC USB2502
DATASHEET
5.2.3.12 EEPROM Offset E(h) - Hub Controller Max Current For Bus Powered Operation
5.2.3.13 EEPROM Offset F(h) - Power-On Time
5.3 SMBus Slave Interface
Instead of loading User-Defined Descriptor data from an external EEPROM, the SMSC Hub can be
configured to receive a code load from an external processor via an SMBus interface. The SMBus
interface shares the same pins as the EEPROM interface, if CFG_SEL1 & CFG_SEL0 activates the
SMBus interface, external EEPROM support is no longer available (and the user-defined descriptor
data must be downloaded via the SMBus). Due to system issues, the SMSC Hub waits indefinitely for
the SMBus code load to complete and only “appears” as a newly connected device on USB after the
code load is complete.
The Hub’s SMBus implementation is a subset of the SMBus interface to the host. The device is a
slave-only SMBus device. The implementation in the device is a subset of SMBus since it only supports
two protocols.
The Write Byte and Read Byte protocols are the only valid SMBus protocols for the Hub. The Hub
responds to other protocols as described in Section 5.3.2, "Invalid Protocol Response Behavior," on
page 25. Reference the System Management Bus Specification, Rev 1.0.
The SMBus interface is used to read and write the registers in the device. The register set is shown
in Section 5.3.9, "Internal SMBus Memory Register Set," on page 26.
5.3.1 Bus Protocols
Typical Write Byte and Read Byte prot ocols are shown below. Register accesses are performed using
7-bit slave addressing, an 8-bit register address field, and an 8-bit data field. The shading indicates
the Hub driving data on the SMBDATA line; otherwise, host data is on the SDA/SMBDATA line.
The slave address is the unique SMBus Interface Address for the Hub that ide ntifies it on SMBus. The
register address field is the internal address of the register to be accessed. The register data field is
the data that the host is attempting to write to the register or the contents of the register that the host
is attempting to read.
Note: Data bytes are transferred MSB first (msb first).
BIT
NUMBER BIT NAME DESCRIPTION
7:0 HC_MAX_C_BP Hub Controller Max Current Bus-Powered: Value in 2mA increments that the
Hub consumes from an upstream port (VBUS) when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value does NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
A value of 50 (decimal) indicates 100mA, which is the default value.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 POWER_ON_TIME Power On Time: The lengt h of time that is takes (in 2 ms intervals) fr om the
time the host initiated power-on sequence begins on a port until power is
good on that port.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 25 Revision 2.3 (08-27-07)
DATASHEET
5.3.1.1 Byte Protocols
When using the Hub SMBus Interface for byte transfers, a write will always consist of the SMBus
Interface Slave Address byte, followed by the Internal Address Register byte, then the data byte.
The normal read protocol consists of a write to the HUB with the SMBus Interface Address byte,
followed by the Internal Address Register byte. Then restart the Serial Communication with a Read
consisting of the SMBus Interface Address byte, followed by the data byte read from the Hub. This
can be accomplished by using the Read Byte protocol.
Note: For the following SMBus tables:
Write Byte
The Write Byte protocol is used to write data to the registers. The data will only be writt en if the protocol
shown in Table 5.2 is performed correctly. Only one byte is transferred at a time for a Write Byte
protocol.
Read Byte
The Read Byte protocol is used to read data from the registers. The data will only be read if the
protocol shown in Table 5.3 is performed correctly. Only one byte is transferred at a time for a Read
Byte protocol.
5.3.2 Invalid Protocol Response Behavior
Registers that are accessed with an invalid protocol are not updated. A register is only updated
following a valid protocol. The only valid protocols are Write Byte and Read Byte, which a re described
above.
The Hub only responds to the hardware selected Slave Address.
Attempting to commun icate with the Hub over SMBus with an invalid slave address or invalid proto col
results in no response, and the SMBus Slave Interface returns to the idle state.
The only valid registers that are accessible by the SMBus slave address are the registers defined in
the Registers Section. See Section 5.3.3 for the response to undefined registers.
5.3.3 General Call Address Response
The Hub does not respond to a general call address of 0000_000b.
Table 5.2 SMBus Write Byte Protocol
Field: Start Slave Addr Wr Ack Reg. Addr Ack Reg. Data Ack Stop
Bits:1 71181811
Table 5.3 SMBus Read Byte Protocol
Field: Start Slave
Addr Wr Ack Reg.
Addr Ack Start Slave
Addr Rd Ack Reg.
Data Nack Stop
Bits: 1 7 1 1 8 1 1 7 1 1 8 1 1
Denotes Master -to-Slave Denotes Slave-to-Master
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 26 SMSC USB2502
DATASHEET
5.3.4 Slave Device Time-Out
According to the SMBus Specification, V1.0 devices in a transfer can abort the transfer in progress
and release the bus when any single clock low interval exceeds 25ms (TTIMEOUT, MIN). Devices that
have detected this condition must reset their communication and be able to receive a new START
condition no later than 35ms (TTIMEOUT, MAX).
Note: Some simple devices do not contain a clock low drive ci rcuit; t his simple kind of device typi cally
resets its communications port after a start or stop condition.
5.3.5 Stretching the SCLK Signal
The Hub supports stretching of the SCLK by other devices on the SMBus. The Hub does not stretch
the SCLK.
5.3.6 SMBus Timing
The SMBus Slave Interface complies with the SMBus AC Timing Specification. See the SMBu s timing
in the “Timing Diagram” section.
5.3.7 Bus Reset Sequence
The SMBus Slave Interface resets and returns to the idle state upon a START field followed
immediately by a STOP field.
5.3.8 SMBus Alert Response Address
The SMBALERT# signal is not supported by the Hub.
5.3.9 Internal SMBus Memory Register Set
The following table provides the SMBus slave interface register map values.
Tabl e 5.4 SMBus Slave Interface Register Map
REG
ADDR R/W REGISTER NAME ABBR BIT 7
(MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
(LSB)
00h R/W Status/Command STCD 7 6 5 4 3 2 1 0
01h R/W VID LSB VIDL 7 6 5 4 3 2 1 0
02hR/WVID MSB VIDM7 6543210
03h R/W PID LSB PIDL 7 6 5 4 3 2 1 0
04hR/WPID MSB PIDM7 6543210
05hR/WDID LSB DIDL7 6543210
06h R/W DID MSB DIDM 7 6 5 4 3 2 1 0
07h R/W Config Data Byte 1 CFG1 7 6 5 4 3 2 1 0
08h R/W Config Data Byte 2 CFG2 7 6 5 4 3 2 1 0
09h R/W Non-Removable
Devices NRD76543210
0Ah R/W Port Disable (Self) PDS 7 6 5 4 3 2 1 0
0Bh R/W Port Disable (Bus) PDB 7 6 5 4 3 2 1 0
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 27 Revision 2.3 (08-27-07)
DATASHEET
5.3.9.1 Register 00h: Status/Command (Reset = 0x00)
5.3.9.2 Register 01h: Vendor ID (LSB) (Reset = 0x00)
0Ch R/W Max Power (Self) MAXPS 7 6 5 4 3 2 1 0
0Dh R/W Max Power (Bus) MAXPB 7 6 5 4 3 2 1 0
0Eh R/W Hub Controller
Max Current (Self) HCMCS 7 6 5 4 3 2 1 0
0Fh R/W Hub Controller
Max Current (bus) HCMCB 7 6 5 4 3 2 1 0
10h R/W Power-on Time PWRT 7 6 5 4 3 2 1 0
BIT
NUMBER BIT NAME DESCRIPTION
7:3 Reserved Reserved. {Note: Software must never write a ‘1’ to these bits}
2 RESET Reset the SMBus Interface and internal memory back to RESET_N assertion
default settings. {Note: During this reset, this bit is automatically cleared to
its default value of 0.}
0 = Normal Run/Idle State.
1 = Force a reset.
1 WRITE_PROT Write Protect: The external SMBu s host sets this bit after the Hub’s internal
memory is loaded with configuration data. {Note: The Ext ernal SMBus Host
is responsible for verification of downloaded data.}
0 = The internal memory (address range 01-10h) is not write protected.
1 = The internal memory (address range 01-10h) is “write-protected” to
prevent unintentional data corruption.}
{Note: This bit is wri te once and is only cleared by assertion of the e xternal
RESET_N pin.}
0 USB_ATTACH USB Attach & power-down the SMBus Interface.
0 = Default; SMBus slave interface is active.
1 = Hub will signal a USB attach event to an upstream device, Note: SMBus
Slave interface will completely power down after the ACK has completed.
{Note: This bit is wri te once and is only cleared by assertion of the e xternal
RESET_N pin.}
BIT
NUMBER BIT NAME DESCRIPTION
7:0 VID_LSB Least Significant Byte of the Vendor ID.
Table 5.4 SMBus Slave Interface Register Map (continued)
REG
ADDR R/W REGISTER NAME ABBR BIT 7
(MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
(LSB)
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 28 SMSC USB2502
DATASHEET
5.3.9.3 Register 02h: Vendor ID (MSB) (Reset = 0x00)
5.3.9.4 Register 03h: Product ID (LSB) (Reset = 0x00)
5.3.9.5 Register 04h: Product ID (MSB) (Reset = 0x00)
5.3.9.6 Register 05h: Device ID (LSB) (Reset = 0x00)
5.3.9.7 Register 06h: Device ID (MSB) (Reset = 0x00)
5.3.9.8 Register 07h: CONFIG_BYTE_1 (Reset = 0x00)
BIT
NUMBER BIT NAME DESCRIPTION
7:0 VID_MSB Most Significant Byte of the Vendor ID.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PID_LSB Least Significant Byte of the Product ID.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PID_MSB Most Significant Byte of the Product ID.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 DID_LSB Least Significant Byte of the Device ID.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 DID_MSB Most Significant Byte of the Device ID.
BIT
NUMBER BIT NAME DESCRIPTION
7 SELF_BUS_PWR Self or Bus Power: Selects between Self- and Bus-Powered operation.
0 = Bus-Powered operation.
1 = Self-Powered operation.
Note: If Dynamic Power Switching is enabled, this bit is ignored and the
SELF_PWR pin is used to det ermine if the hub is operating from self or bu s
power.
6 Reserved Reserved
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 29 Revision 2.3 (08-27-07)
DATASHEET
5.3.9.9 Register 08h: Configuration Data Byte 2 (Reset = 0x00)
5 HS_DISABLE High Speed Disable: Disables the capability to attach as either a High/Full-
speed device, and force s attachment as Full-speed only i.e. (no High -Speed
support).
0 = High-/Full-Speed.
1 = Full-Speed-Only (High-Speed disabled!)
4 Reserved Reserved
3 EOP_DISABLE EOP Disable: Disables EOP generation of EOF1 when in Full-Speed mode.
0 = EOP generation is normal.
1 = EOP generation is disabled.
2:1 CURRENT_SNS Over Current Sense: Indicates whether current sensing isganged.
00 = Ganged sensing (all ports together).
01 = Reserved1x = Over current sensing not supported. (must only be used
with Bus-Powered configurations!)
0 Reserved Reserved
BIT
NUMBER BIT NAME DESCRIPTION
7 DYNAMIC Dynamic Power Enable: Controls the ability for the Hub to transition to Bus-
Powered operati on if the local power source is removed (can revert back to
Self-Power if local power source is restored).
0 = No Dynamic auto-switching.
1 = Dynamic Auto-switching capable.
6 Reserved Reserved
5:4 OC_TIMER OverCurrent Timer: Over Current Timer delay.
00 = 0.1ms
01 = 2ms
10 = 4ms
11 = 6 m s
3 COMPOUND Compound Device: Designates if Hub is part of a compound device.
0 = No.
1 = Yes, Hub is part of a compound device.
2:0 Reserved Reserved
BIT
NUMBER BIT NAME DESCRIPTION
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 30 SMSC USB2502
DATASHEET
5.3.9.10 Register 09h: Non-Removable Device (Reset = 0x00)
5.3.9.11 Register 0Ah: Port Disable For Self Powered Operation (Reset = 0x00)
5.3.9.12 Register 0Bh: Port Disable For Bus Powered Operation (Reset = 0x00)
5.3.9.13 Register 0Ch: Max Power For Self Powered Operation (Reset = 0x00)
BIT
NUMBER BIT NAME DESCRIPTION
7:0 NR_DEVICE Non-Removable Device: Indicates which port(s) include non-removable devic-
es. ‘0’ = port is removable , ‘1’ = port is non-removable.
Bit 7:3: Reserved, always = ‘0’
Bit 2= 1; Port 2 non-removable.
Bit 1= 1; Port 1 non removable.
Bit 0 is Reserved, always = ‘0’.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PORT_DIS_SP Port Disable Self-Powered: Disables 1 or more contiguous ports. ‘0’ = port
is available, ‘1’ = port is disabled.
Bit 7:3= 0; ReservedBit 2= 1; Port 2 is disabled.
Bit 1= 1; Port 1 is disabled.
Bit 0 is Reserved, always = ‘0’
BIT
NUMBER BIT NAME DESCRIPTION
7:0 PORT_DIS_BP Port Disable Bus-Powered: Disables 1 or more contiguous ports. ‘0’ = port
is available, ‘1’ = port is disabled.
Bit 7:3= 0; ReservedBit 2= 1; Port 2 is disabled.
Bit 1= 1; Port 1 is disabled.
Bit 0 is Reserved, always = ‘0’
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_SP Max Power Self _Powere d: Value in 2mA increments that the Hub consumes
from an upstream port (VBUS) when operating as a self-powered hub. This
value includes the hub silicon along with the combined power consumption
(from VBUS) of all associated circuitry on the board. This value also includes
the power consumption of a permanently attached peripheral if the hub is
configured as a compound device, and the embedded peripheral reports
0mA in its descriptors.
Note: The USB 2.0 Specification does not permit this value to exceed
100mA
A value of 50 (decimal) indicates 100mA.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 31 Revision 2.3 (08-27-07)
DATASHEET
5.3.9.14 Register 0Dh: Max Power For Bus Powered Operation (Reset = 0x00)
5.3.9.15 Register 0Eh: Hub Controller Max Current For Self Powered Operation (Reset = 0x00)
5.3.9.16 Register 0Fh: Hub Controller Max Current For Bus Powered Operation (Reset = 0x00)
5.3.9.17 Register 10h: Power-On Time (Reset = 0x00)
5.3.9.18 Undefined Registers
The registers shown in Table 5.4 are the defined registers in the Hub. Reads to undefined registers
return 00h. Writes to undefined registers have no effect and do not return an error.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_BP Max Power Bus_Powe re d: Value in 2mA increments that the Hub consumes
from an upstream port (VBUS) when operating a s a bus-powered hub. This
value includes the hub silicon along with the combined power consumption
(from VBUS) of all associated circuitry on the board. This value also includes
the power consumption of a permanently attached peripheral if the hub is
configured as a compound device, and the embedded peripheral reports
0mA in its descriptors.
A value of 50 (decimal) indicates 100mA.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 HC_MAX_C_SP Hub Controller Max Current Self-Powered: Value in 2mA increments that the
Hub consumes from an upstream port (VBUS) when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value does NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
Note: The USB 2.0 Specification does not permit this value to exceed
100mA
A value of 50 (decimal) indicates 100mA, which is the default value.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 HC_MAX_C_BP Hub Controller Max Current Bus-Powered: Value in 2mA increments that the
Hub consumes from an upstream port (VBUS) when operating as a bus-
powered hub. This value will include the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value will NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
A value of 50 (decimal) would indicate 100mA, which is the default value.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 POWER_ON_TIME Power On Time: The length of time that it takes (in 2 ms intervals) from the
time the host initiated power-on sequence begins on a port until power is
good on that port.
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 32 SMSC USB2502
DATASHEET
5.3.9.19 Reserved Registers
Unless otherwise instructed, only a ‘0’ may be written to all reserved registers or bits.
5.4 Default Configuration Option:
The SMSC Hub can be config ured via its internal default conf iguration. (please see for speci fic details
on how to enable default configuration.
Please refer to Table 5 .1 on page 19 for the internal default values that are loaded when this option is
selected.
5.5 Default Strapping Options:
The SMSC Hub can be configured via a combination of internal default values and pin strap options.
Please see Table 4.1, "7-Port Hub Pin Descriptions" for specific details on how to enable the
default/pin-strap configuration option.
The strapping op tion pins only cover a limited sub -set of the configurat ion options. The internal d efault
values will be used for the bits & registers that are not controlled by a strapping option pin. Please
refer to Table 5.1 on page 19 for the internal default values that are loaded when this option is selected.
The Green LED pins are sampled after RESET_N negation , and the logic val ues are used to configure
the hub if the internal default configuration mode is selected. The implementation shown below (see
Figure 5.1) shows a recommended passive scheme. When a pin is configured with a “Strap High”
configuration, the LED functions with active low signalling, and the PAD will “sink” the current from the
external supply. When a pin is configured with a “Strap Low” configuration, the LED functions with
active high signalling, and the PAD will “source” the current to the external LED.
Figure 5.1 LED Strapping Option
5.6 Reset
There are two different resets that the Hub experiences. One is a hardware reset (via the RESET_N
pin) and the second is a USB Bus Reset.
HUB
50K
Strap Low
GR2
50K
Strap High
GR1
+V
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 33 Revision 2.3 (08-27-07)
DATASHEET
5.6.1 External Hardware RESET_N
A valid hardware reset is defined as, assertion of RESET_N for a minimum of 1us after all power
supplies are within operating range. While reset is asserted, the Hub (and its associated external
circuitry) consumes less than 500μA of current from the upstream USB power source (300μA for the
Hub and 200μA for the external circuitry).
Assertion of RESET_N (external pin) causes the following:
1. All downstream ports are disabled, and PRTPWR power to downstream devices is removed.
2. The PHYs are disabled, and the differential pairs will be in a high-impedance state.
3. All transactions immediately terminate; no states are saved.
4. All internal registers return to the default state (in most cases, 00(h)).
5. The external crystal oscillator is halted.
6. The PLL is halted.
7. LED indicators are disabled.
The Hub is “operational” 500μs after RESET_N is negated.
Once operational, the Hub immediately reads OEM-specific data from the external EEPROM (if the
SMBus option is not disabled).
5.6.1.1 RESET_N for Strapping Option Configuration
Figure 5.2 Reset_N Timing for Default/Strap Option Mode
Table 5.5 Reset_N Timing for Default/Strap Option Mode
NAME DESCRIPTION MIN TYP MAX UNITS
t1 RESET_N Asserted. 1 μsec
t2 Strap Setup Time 16.7 nsec
t3 Strap Hold Time. 16.7 1400 nsec
t4 hub outputs driven to inactive logic states 2.0 1.5 μsec
t5 USB Attach (See Note). 100 msec
t1
t4
t5 t6 t7 t8
Valid Don’t Care
Don’t Care Driven by Hub if strap is an output.
RESET_N
VSS
Strap Pins
VSS
Hardware
reset
asserted
Read Strap
Options
Drive Strap
Outputs to
inactive
levels
Attach
USB
Upstream
USB Reset
recovery Idle
Start
completion
request
response
t2 t3
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 34 SMSC USB2502
DATASHEET
Notes:
When in Bus-Powered mode, the Hub and its associated circuitry must not consume more than
100mA from the upstream USB power source during t1+t5.
All Power Supplies must have reached the operating levels mandated in Section Chapter 7, "DC
Parameters", prior to (or coincident with) the assertion of RESET_N.
5.6.1.2 RESET_N for EEPROM Configuration
Figure 5.3 Reset_N Timing for EEPROM Mode
Notes:
When in Bus-Powered mode, the Hub and its associated circuitry must not consume more than
100mA from the upstream USB power source during t4+t5+t6+t7.
t6 Host acknowledges attach and signals USB
Reset. 100 msec
t7 USB Idle. undefined msec
t8 Completion t ime for requ ests (with or wit hout d ata
stage). 5msec
Table 5.6 Reset_N Timing for EEPROM Mode
NAME DESCRIPTION MIN TYP MAX UNITS
t1 RESET_N Asserted. 1 μsec
t2 Hub Recovery/Stabilization. 500 μsec
t3 EEPROM Read / Hub Config. 2.0 99.5 msec
t4 USB Attach (See Note). 100 msec
t5 Host acknowledges attach and signals USB
Reset. 100 msec
t6 USB Idle. undefined msec
t7 Completion t ime for requ ests (with or wit hout d ata
stage). 5msec
Table 5.5 Reset_N Timing for Default/Strap Option Mode (continued)
NAME DESCRIPTION MIN TYP MAX UNITS
t1 t2 t4 t5 t6 t7
RESET_N
VSS
Hardware
reset
asserted
Read Strap
Options
Read EEPROM
+
Set Options
Attach
USB
Upstream
USB Reset
recovery Idle
Start
completion
request
response
t3
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 35 Revision 2.3 (08-27-07)
DATASHEET
All Power Supplies must have reached the operating levels mandated in Section Chapter 7, "DC
Parameters", prior to (or coincident with) the assertion of RESET_N.
5.6.1.3 RESET_N for SMBus Slave Configuration
Figure 5.4 Reset_N Timing for SMBus Mode
Notes:
For Bus-Powered configurations, the 99.5ms (MAX) is required, and the Hub and its associated
circuitry must not consume more than 100mA from the upstream USB power source during
t2+t3+t4+t5+t 6+t7. For Self-Powered configurations, t 3 MAX is not applicable and the time t o load
the configuration is determined by the external SMBus host.
All Power Supplies must have reached the operating levels mandated in Section Chapter 7, "DC
Parameters", prior to (or coincident with) the assertion of RESET_N.
Table 5.7 Reset_N Timing for SMBus Mode
NAME DESCRIPTION MIN TYP MAX UNITS
t1 RESET_N Asserted. 1 μsec
t2 Hub Recovery/Stabilization. 500 μsec
t3 SMBus Code Load (See Note). 10 99.5 msec
t4 Hub Configuration and USB Attach. 100 msec
t5 Host acknowledges attach and signals USB
Reset. 100 msec
t6 USB Idle. Undefined msec
t7 Completion time for requests (with or without data
stage). 5msec
t1 t2 t4 t5 t6 t7
RESET_N
VSS
Hardware
reset
asserted
Reset
Negation SMBus Code
Load
Attach
USB
Upstream
USB Reset
recovery Idle
Start
completion
request
response
t3
Hub PHY
Stabilization
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 36 SMSC USB2502
DATASHEET
5.6.2 USB Bus Reset
In response to the upstream port signaling a reset to the Hub, the Hub does the following:
Note: The Hub does not propagate the upstream USB reset to downstream devices.
1. Sets default address to 0.
2. Sets configuration to: Unconfigured.
3. Negates PRTPWR to all downstream ports.
4. Clears all TT buffers.
5. Moves device from suspended to active (if suspended).
6. Complies with Section 11.10 of the USB 2.0 Specification for behavior after completi on of the reset
sequence.
The Host then configu res the Hub and the Hub’s downstream port devices in accord ance with the USB
Specification.
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 37 Revision 2.3 (08-27-07)
DATASHEET
Chapter 6 XNOR Test
XNOR continuity tests all signal pins on the Hub (every pin except for NC, XTAL1/CLKIN, XTAL2,
ATEST/REG_EN, RBIAS, TEST, Power, and Ground). This functionality is enabled by driving TEST
and CFG_SEL[1] high, driving SCLK low and transition RESET_N from low to high. The output from
the XNOR chain is driven to GR2 . For each pin tested for continuity GR2 should toggle.
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 38 SMSC USB2502
DATASHEET
Chapter 7 DC Parameters
7.1 Maximum Guaranteed Ratings
Note: Stresses above the specified parameters could cause permanent damage to the device. This
is a stress rating only and functional operation of the device at any 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 outpu ts when the AC power is switched on or off. In addi tion, voltage transients
on the AC power line may app ear on the DC outp ut . Wh en this p ossibi lity exists, it is suggest ed
that a clamp circuit be used.
PARAMETER SYMBOL MIN MAX UNITS COMMENTS
Storage
Temperature TA-55 150 °C
Lead
Temperature 325 °C Soldering < 10 seconds
1.8V supply
voltage VDDA18PLL
VDD18 -0.3 2.5 V
3.3V supply
voltage VDDA33
VDDA33PLL
VDD33CR
-0.3 4.0 V
V oltage on any
I/O pin -0.3 (3.3V supply voltage + 2) ≤ 6V
Voltage on
XTAL1 -0.3 4.0 V
Voltage on
XTAL2 -0.3 VDD18 + 0.3V V
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 39 Revision 2.3 (08-27-07)
DATASHEET
7.2 Recommended Operating Conditions
PARAMETER SYMBOL MIN MAX UNITS COMMENTS
Operating
Temperature TA070°C
1.8V supply voltage VDDA18PLL
VDD18 1.62 1.98 V
3.3V supply voltage VDDA33
VDDA33PLL
VDD33CR
3.0 3.6 V
Voltage on any I/O pin -0.3 5.5 V If any 3.3 V sup ply voltage drops
below 3.0V, then the MAX
becomes:
(3.3V supply voltage + 0.5)
Voltage on XTAL1 -0.3 VDDA33 V
Voltage on XTAL2 -0.3 VDD18 V
Table 7.1 DC Electrical Characteristics
PARAMETER SYMBOL MIN TYP MAX UNITS COMMENTS
I, IS Type Input Buffer
Low Input Level
High Input Leve l
Input Leakage
Hysteresis (‘IS’ Only)
VILI
VIHI
IIL
VHYSI
2.0
-10
250 300
0.8
+10
350
V
V
uA
mV
TTL Levels
VIN = 0 to VDD33CR
Input Buffer with Pull-Up
(IPU)
Low Input Level
High Input Le ve l
Low Input Leakage
High Input Leakage
VILI
VIHI
IILL
IIHL
2.0
+5
-10
0.8
+45
+10
V
V
uA
uA
TTL Levels
VIN = 0
VIN = VDD33CR
Input Buffer with Pull-Down
IPD
Low Input Level
High Input Le ve l
Low Input Leakage
High Input Leakage
VILI
VIHI
IILL
IIHL
2.0
+10
-80
0.8
-10
-160
V
V
uA
uA
TTL Levels
VIN = 0
VIN = VDD33CR
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 40 SMSC USB2502
DATASHEET
ICLK Input Buffe r
Low Input Level
High Input Leve l
Input Leakage
Hysteresis
VILCK
VIHCK
IIL
VHYSC
2.0
-10
50
0.8
+10
100
V
V
uA
mV
TTL Levels
VIN = 0 to VDD33CR
O8 and I/O8 Type Buffer
Low Output Level
High Output Level
Output Leakage
VOL
VOH
IOL
2.4
-10
0.4
+10
V
V
uA
IOL = 8 mA @ VDD33CR = 3.3V
IOH = -4mA @ VDD33CR = 3.3V
VIN = 0 to VDD33CR
(Note 1)
I/OSD12 Type Buffer
Low Output Level
Output Leakage
Hysteresis
VOL
IOL
VHYSI
-10
250 300
0.4
+10
350
V
µA
mV
IOL = 12 mA @ VDD33CR = 3.3V
VIN = 0 to VDD33CR
(Note 1)
IO-U
(Note 2)
I-R
(Note 3)
Supply Current Unconfig-
ured
High-Speed Host
Full-Speed Host ICCINIT
ICCINIT 73
65 mA
mA
Supply Current
Configured
(High-Speed Host)
2 Ports @ FS/LS
2 Ports @ HS
1 Port HS, 1 Port FS/LS
IHCC2
IHCH2
IHCH1C1
120
170
140
mA
mA
mA
Total from all supplies
Supply Current
Configured
(Full-Speed Host)
1 Port
2 Ports IFCC1
IFCC2 90
90
mA
mA
Total from all supplies
Table 7.1 DC Electrical Characteristics (continued)
PARAMETER SYMBOL MIN TYP MAX UNITS COMMENTS
2-Port USB 2.0 Hub Controller
Datasheet
SMSC USB2502 41 Revision 2.3 (08-27-07)
DATASHEET
Notes:
1. Output leakage is measured with the current pins in high impedance.
2. See USB 2.0 Specification for USB DC electrical characteristics.
3. RBIAS is a 3.3V tolerant analog pin.
CAPACITANCE TA = 25°C; fc = 1MHz; VDD33CR = 3.3V
Power Sequencing
There are no power supply sequence restrictions for the Hub. The order in which power supplies
power-up and power-down is implementation dependent.
Supply Current
Suspend ICSBY 320 425 uA Total from all supplies.
Supply Current
Reset IRST 160 300 uA Total from all supplies.
LIMITS
PARAMETER SYMBOL MIN TYP MAX UNIT TEST CONDITION
Clock Input
Capacitance CIN 12 pF All pins except USB pi ns (and pins under
test tied to AC ground)
Input Capacitance CIN 8pF
Output Capacitance COUT 12 pF
Table 7.1 DC Electrical Characteristics (continued)
PARAMETER SYMBOL MIN TYP MAX UNITS COMMENTS
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 42 SMSC USB2502
DATASHEET
Chapter 8 AC Specifications
8.1 Oscillator/Clock
Crystal: Parallel Resonant, Fundamental Mode, 24 MHz ±100ppm.
External Clock: 50% Duty cycle ± 10%, 24 MHz ± 100ppm, Jitter < 100ps rms.
8.1.1 SMBus Interface:
The SMSC Hub conforms to all voltage, power, and timing characteristics and specifications as set
forth in the SMBus 1.0 Specification for Slave-Only devices (except as noted in Section 5.3).
8.1.2 I2C EEPROM:
Frequency is fixed at 59KHz ± 20%.
8.1.3 USB 2.0
The Hub conforms to all voltage, power, and timing characteristics and specifications as set forth in
the USB 2.0 Specification. Please refer to the USB Specification for more information.
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 43 SMSC USB2502
DATASHEET
Chapter 9 Package Outlines
Figure 9.1 36 Pin QFN Package
-SEE SPE C F R O NT P A GE F OR REVISION HISTORY --
DECIMAL
X.X
X.XX
X.XXX
MATERIAL
FINISH
STD COMPLIAN C E
THIRD ANGLE PROJECTION
PRIN T WITH "S CA LE TO FIT"
DO N OT SC A LE DRAWING
APPROVED
ANGULAR
UNLESS OTHERWISE SPECIFIED
DIMENSIONS A RE IN MILLIMETERS
AND TOLERANCES ARE:
DIM A ND T OL PER AS ME Y14.5M - 1994
DRAWN
CHECKED
NAME
SCALE
80 ARK A Y DRIVE
HAUPPAUGE, NY 11788
USA
DW G NUM BER
TITLE
DATE
SHEET
REV
REVISION HISTORY
DESCRIPTIONREVISION RELEASED BYDATE
S.K.ILIEV
S.K.ILIEV
S.K.ILIEV
±1°
-
-
±0.025
±0.05
±0.1
12/6/04 1:1
12/6/04
12/6/04 F
JEDEC: MO-220 1 OF 1
36 TERMINAL QFN, 6x6mm BODY, 0.5mm PITCH
PACKAG E OU T LINE
MO-36-QFN-6x6
SIDE VIEW
3-D VIEWS
TOP VIEW
3
2
BOTTO M VIEW
NOTES:
1. ALL DIMENSIONS ARE IN MILLIMETER.
2. POSITION TOLERANCE OF EACH TERMINAL IS ± 0.05mm AT MAXIMUM MATERIAL CONDITION. DIMENSIONS
"b" APPL I ES TO PLATED TERM INALS AND IT IS MEASURED BETWEE N 0.15 AND 0.30 mm FROM THE
TERMI N AL TI P.
3. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL BUT MUST BE LOCATED WITHIN THE AREA INDICATED.
4. COPL ANARITY ZONE APPLI ES TO EXPOSED PAD AND TERMINALS.
E2EE1
0.6(MAX)
0.6(MAX)
D
D1
TERMI NAL #1
IDENTIFIER AREA
(D1/2 X E1/2)
36X b
36X L
TERM I NA L # 1
IDEN TIFI ER AREA
(D/2 X E/2)
D2
e
EXPOSED PAD
3
A1
A2 A
CHAMFERED CORNERS
ARE OPTIONAL 4X
36X 0.2 MIN
4
ccc C
4
C
A3
4X 0°-12°
D2 / E2 V ARIATIONS
CATALOG PART
2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 44 SMSC USB2502
DATASHEET
Figure 9.2 48 Pin TQFP Package Outline (7x7x1.4 mm body, 2mm Footprint)
Notes:
1. Controlling Unit: millimeter.
2. Tolerance on the true position of the leads is ± 0.04 mm maximum.
3. Package body dimensions D1 and E1 do not include the mold protrusion.
Maximum mold protrusion is 0.25 mm.
4. Dimension for foot length L measured at the gauge plane 0.25 mm above the seating plane.
5. Details of pin 1 identifier are optional but must be located within the zone indicated.
Table 9.1 48 Pin TQFP Package
MIN NOMINAL MAX REMARKS
A ~ ~ 1.60 Overall Package Height
A1 0.05 ~ 0.15 Standoff
A2 1.35 ~ 1.45 Body Thickness
D 8.80 ~ 9.20 X Span
D1 6.90 ~ 7.10 X body Size
E 8.80 ~ 9.20 Y Span
E1 6.90 ~ 7.10 Y body Size
H 0.09 ~ 0.20 Lead Frame Thickness
L 0.45 0.60 0.75 Lead Foot Length
L1 ~ 1.00 ~ Lead Length
e0.50 Basic Lead Pitch
θ0o~7
oLead Foot Angle
W 0.17 0.22 0.27 Lead Width
R1 0.08 ~ ~ Lead Shoulder Radius
R2 0.08 ~ 0.20 Lead Foot Radius
ccc ~ ~ 0.08 Coplanarity