SMSC USB2503/USB2503A DATASHEET Revision 2.3 (08-27-07)
Datasheet
PRODUCT FEATURES
USB2503/
USB2503A
Integrated USB 2.0
Compatible 3-Port Hub
Integrated USB 2.0 Compatible 3-Port Hub
— 3 Transaction Translators for highest performance
— High-Speed (480Mbits/s), Full-Speed (12Mbits/s) and
Low-Speed (1.5Mbits/s) compatible
— Full power management with per port or ganged,
selectable 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
1.8 Volt Low Power Core Operation
3.3 Volt I/O with 5V Input Tolerance
48 Pin QFN lead-free RoHS compliant package
ORDER NUMBERS:
USB2503/USB2503A-HZH FOR 48 PIN QFN LEAD-FREE ROHS COMPLIANT PACKAGE
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 2 SMSC USB2503/USB2503A
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 inaccura cies. 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 nam es 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, PR OFITS, SAVINGS OR REVENUES OF ANY KIND ; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT;
TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BRE ACH OF WARRANTY; OR OTHERWISE ; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD
TO HAVE FAILED OF ITS ES SENTIAL PURPOSE, AND WHETHER OR NOT SMSC HA S BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 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 3-Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 3 Pin Configuration 3-Port Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 4 3-Port Hub Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 5 Functional Block Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1 3-Port Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1.1 Hub Configuration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1.2 VBus Detect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2 EEPROM Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.1 I2C EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.2 In-Circuit EEPROM Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2.3 EEPROM DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.3 SMBus Slave Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.3.1 Bus Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.3.2 Invalid Protocol Response Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.3 General Call Address Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.4 Slave Device Time-Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.5 Stretching the SCLK Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.6 SMBus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.7 Bus Reset Sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.8 SMBus Alert Response Address. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.9 Internal SMBus Memory Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.4 Default Configuration Option: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5 Default Strapping Options: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.6 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.6.1 External Hardware RESET_N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.6.2 USB Bus Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
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 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 4 SMSC USB2503/USB2503A
DATASHEET
List of Figures
Figure 3.1 3-Port 48-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 4.1 3-Port Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
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 48 Pin QFN Package Outline (7x7 mm body - 0.5 mm pitch) . . . . . . . . . . . . . . . . . . . . . . . . 43
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 5 Revision 2.3 (08-27-07)
DATASHEET
List of Tables
Table 4.1 3-Port Hub Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 4.2 SMBus or EEPROM Interface Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 4.3 Miscellaneous Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 4.4 Power, Ground, and No Connect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 4.5 Buffer Type Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 5.1 User-Defined Descriptor Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 5.2 SMBus Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 5.3 SMBus Read Byte Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 5.4 SMBus Slave Interface Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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 QFN Package Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 6 SMSC USB2503/USB2503A
DATASHEET
Chapter 1 General Description
The SMSC 3-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 3-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.
A dedicated Transa ction Translator (TT) is available for each downstream fa cing port. This architecture
ensures maximum USB throughput for each connected device when operating with mixed-speed
peripherals.
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 p orts are integrated in to the Hub. This includes a ll series termination
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 USB2503/USB2503A following a reset. This configuration
may be sufficient for some applications. Strapping option pins make it possibl e to modify a limited sub-
set of the configuration options.
The USB2503/USB25 03A may also be configured by an external EEPROM or a microcontroll er. 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 3-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).
Multiple Transaction Translator (Multi-TT) or Single-TT support.
Optional OEM configuration via I2C EEPROM or via the industry standard SMBus interface from
an external SMBus Host.
Port power switching on an individual or ganged basis.
Port over-current monitoring on an individual or ganged basis.
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)
Port Disable
Ganged Vs Port power switching and over-current sensing
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 7 Revision 2.3 (08-27-07)
DATASHEET
Chapter 2 Pin Table 3-Port
Table 2.1 3-Port Pin Table
UPSTREAM USB 2.0 INTERFACE (3-PINS)
USBDP0 USBDN0 VBUS_DET
3-PORT USB INTERFACE (18-PINS)
USBDP1 USBDN1 USBDP2 USBDN2
USBDP3 USBDN3 GR1/
NON_REM0 GR2/
NON_REM1
GR3/
PRT_DIS0 PRTPWR1 PRTPWR2 PRTPWR3
PRTPWR_POL OCS1_N OCS2_N OCS3_N
GANG_EN RBIAS
SERIAL PORT (3-PINS)
SDA/SMBDATA SCL/SMB-
CLK/CFG_SEL0 CFG_SEL1
MISC (8-PINS)
XTAL1/CLKIN XTAL2 RESET_N SELF_PWR
TEST1 TEST0 ATEST/
REG_EN CLKIN_EN
POWER & GROUNDS (16-PINS)
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 8 SMSC USB2503/USB2503A
DATASHEET
Chapter 3 Pin Configuration 3-Port Hub
Figure 3.1 3-Port 48-Pin QFN
Thermal Slug
(must be connected to VSS)
SMSC
USB2503
&
USB2503A
(Top View QFN-48)
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
VSS 10
USBDN3 11
USBDP3 12
24 TEST0
23 VDD18
22 VSS
21 GR1/NON_REM0
20 GANG_EN
19 GR2/NON_REM1
18 PRTPWR_POL
17 GR3/PRT_DIS0
16 PRTPWR2
15 OCS3_N
14 PRTPWER3
13 VDDA33
RESET_N 37
VSS 38
VDD33CR 39
VDD18 40
VSS 41
XTAL1/CLKIN 43
VDDA18PLL 44
VDDA33PLL 45
VSS 48
RBIAS 47
ATEST/REG_EN 46
XTAL2 42
35 CLKIN_EN
34 OCS1_N
33 PRTPWR1
32 OCS2_N
31 VDD18
30 VSS
29 VBUS_DET
28 SELF_PWR
26 SCL/SMBCLK/CFG_SEL0
25 SDA/SMBDATA
27 CFG_SEL1
36 TEST1
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 9 Revision 2.3 (08-27-07)
DATASHEET
Chapter 4 3-Port Hub Block Diagram
Figure 4.1 3-Port Block Diagram
Table 4.1 3-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 USB bus data signals.
Detect Upstream
VBUS Power VBUS_DET I/O12 Detects state of Upstream VBUS power (indicates the
power-managed state of the upstream device).
Upstream
VBUS
Upstream
PHY
Upstream
USB Data
Repeater Controller
SIE
Serial
Interface
PLL
24 MHz
Crystal
To
EEPROM
or SMBus
Master
Routing Logic
SCLSD
TT
#1 TT
#2 TT
#3 Port
Controller
Downstream
PHY #1
Port #1
OC Sense
Switch Driver
LED Drivers
Downstream
PHY #3
Port #3
OC Sense
Switch Driv er
LED Drivers
...
Downstream
USB Data OC
Sense Switch/LED
Drivers Downstream
USB Data OC
SenseSwitch/LED
Drivers
VBUS
Power
Detect
Pin
Strapping
Options
Internal
Defaults
Select
3.3V
1.8V
Reg.
1.8V
Cap
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 10 SMSC USB2503/USB2503A
DATASHEET
3-PORT USB 2.0 HUB INTERFACE
High-Speed USB
Data USBDN[3:1]
USBDP[3:1] IO-U These pins connect to the downstream USB peripheral
devices attached to the Hub’s ports.
USB Power
Enable PRTPWR[3:1] O12 Enables power to USB peripheral devices (downstream).
The active signal level of the PRTPWR[3:1] pins are
determined by the Power Polarity Strapping function of the
PRTPWR_POL pin.
Port 3 Green LED
&
Port Disable
strapping option.
GR3/
PRT_DIS0 I/O12 Green indicator LED for port 3. 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 iguration ,
these pins will be sampled at RESET_N negation to
determine if port 3 will be permanently disabled. Also, the
active state of the LED will be determined as follows:
PRT_DIS0 = ‘0’, All ports are enabled,
GR3 is active high.
PRT_DIS0 = ‘1’, Port 3 is disabled,
GR3 is active low.
Port [2:1] Green
LED
&
Port Non-
Removable
strapping option.
GR[2:1]/
NON_REM[1:0] I/O12 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 iguration ,
these pins will be sampled at RESET_N negation to
determine if ports [3:1] 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,
G R2 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, & 3 are non-removable,
GR2 is active low,
GR1 is active low.
Gang Power
Switching and
Current Sensing
strapping option.
GANG_EN I/O12 If the hub is configure d by the interna l defaul t config uration,
this pin will be sampled at RESET_N negation to determine
if downstream port power switching and current sensing are
ganged, or individual port-by-port.
‘0’ = Port-by-port sensing & switching.
‘1’ = Ganged sensing & switching.
Table 4.1 3-Port Hub Pin Descriptions (continued)
NAME SYMBOL TYPE FUNCTION
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 11 Revision 2.3 (08-27-07)
DATASHEET
Port Power
Polarity strapping. PRTPWR_POL I/O12 Port Power Polarity strapping determination for the active
signal polarity of the PRTPWR[3:1] pins.
While RESET_N is asserted, the logic state of this pin will
(though the use of internal combinatorial logic) determine
the active state of t he PRTPWR[3:1] pin s in order to ensu re
that downstrea m port power is not inadvertently ena bled to
inactive ports during a hardware reset.
When RESET_N is negated, the logic value will be latched
internally, and will retain the active signal polarity for
PRTPWR[3:1] pins.
‘1’ = PRTPWR[3:1] pins have an active ‘high’ polartity
‘0’ = PRTPWR[3:1] pins have an active ‘low’ polarity
Over Current
Sense OCS[3:1]_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.
SERIAL PORT INTERFACE
Serial Data/SMB
Data SDA/SMBDATA IOSD12 (Serial Data)/(SMB Data) signal.
Serial Clock/SMB
Clock
&
Chip Select /
EEPROM Select
SCL/SMBCLK/
CFG_SEL0 IOSD12 (Serial Clock)/(SMB Clock) signal. This multifunction pin is
read on the rising edge of RESET_N negation and will
determine the hub configuration method as described in
Table 4.2.
SMB
Programming
Select
CFG_SEL1 I This pin is read on the rising edge of RESET_N negation
and will detemine the hub configuration method as
described in Table 4.2.
Table 4.2 SMBus or EEPROM In terface Behavior
CFG_SEL1 CFG_SEL0 SMBus or EEPROM interface behavior.
0 X Configured as an SMBus slave for external download of user-defined
descriptors. SMBus slave address is :0101101
1 0 Internal Default Configuration via strapping options.
1 1 2-wire (I2C) EEPROMS are supported, and CFG_SEL0 has no other
functionality.
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.
Table 4.1 3-Port Hub Pin Descriptions (continued)
NAME SYMBOL TYPE FUNCTION
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 12 SMSC USB2503/USB2503A
DATASHEET
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 IClock 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 100ns.
Self-Power /
Bus-Power
Detect
SELF_PWR IDetects availability of local self-power source.
Low = Self/local power source is NOT available (i.e., 7-
Port Hub gets all power from Upstream USB VBus).
High = Self/local power source is available.
TEST Pins TEST[1:0] IPD Used for testing the chip. User must treat as a no-
connect or connect to ground. For board testing, all
signal pins are included in an XNOR chain, Please see
Chapter 6, "XNOR Test," on page 37 for more details on
the configuration and use of the XNOR mode.
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 VDDA3P3 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, Gr ound, and No Connect
NAME SYMBOL TYPE FUNCTION
VDD1P8 VDD18 +1.8V core power.
If the internal regulator is enabled, then VDD18 pin
closest to VDD33CR must have a 4.7μF (or greater)
±20% (ESR <0.1Ω) capacitor to VSS
VDDPLL1P8 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
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
VDDA3P3 VDDA33 +3.3V Filtered analog power.
Table 4.3 Miscellaneous Pins (continued)
NAME SYMBOL TYPE FUNCTION
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 13 Revision 2.3 (08-27-07)
DATASHEET
VDD3P3
CORE
PLL
VDD33CR +3.3V I/O and Core 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.
O12 Output 12mA.
I/O12 Input/Output, 12mA
IOSD12 Open drain….12mA sink with Schmitt trigger, and must meet I2C-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 operating as a 1. 1-compliant d evice and meets USB
2.0 requirements when operating as a 2.0-compliant device.
AIO Analog Input/output. Per PHY test requirements.
Table 4.4 Power, Ground, and No Conn ect (co nti nu ed )
NAME SYMBOL TYPE FUNCTION
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 14 SMSC USB2503/USB2503A
DATASHEET
Chapter 5 Functional Block Description
5.1 3-Port Hub
SMSC’s USB 2.0 3-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 3-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 per externally availabl e
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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 15 Revision 2.3 (08-27-07)
DATASHEET
5.1.1.5 Port Indicators
Controls the use of LED indicator for Port status information. See Section 11.5.3 of the USB 2.0
Specification for additional details.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.6 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.
5.1.1.7 Multiple-TT Support
Selects between a mode where only one transaction translator is available for all ports (Single-TT), or
each port gets a dedicate d transaction tr anslator (Mult i-TT) {Note: The host may force Sing le-TT mode
only}.
This field is set by the OEM using either the SMBus or EEPROM interface options.
5.1.1.8 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.
5.1.1.9 Current Sensing
Selects current sensing on a port-by-port basis, all ports ganged, or none(only for bus-powered
hubs)The ability to support current sensing on a port or ganged basis is hardware implementation
dependent.
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)
5.1.1.10 Downstream Port Power Enabling
Enables all ports simultaneously (ganged), or port power is individually switched on and off on a port-
by-port basis. The ability to support power enabling on a port or ganged basis is hardware
implementation dependent.
This field is set by the OEM using either the SMBus or EEPROM interface options. When using the
internal default option, the GANG_EN pin will configure the hub for ganged or individual port-by-port
port power switching.
5.1.1.11 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 au tomatically causes
the hub controller to report that it is part of a compound device.
5.1.1.12 Non-Removable Device
Informs the Host if one of the act ive ports has a perma nent device that is undetachable from the Hub.
(Note: The device must provide its own descriptor data.)
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 16 SMSC USB2503/USB2503A
DATASHEET
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.
5.1.1.13 Self-Powered Port DISABLE
During Self-Powered operation, this selects the ports which will be permanently disabled, and are not
available to be enabled or enumerated by a Host Controller. The disabled ports must be contiguous,
and must be in decreasing order starting with port 3.
This field is set by the OEM using either the SMBus or EEPROM interface options. When using the
internal default option, the PRT_DIS0 pin will disable the appropriate ports.
5.1.1.14 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 enumerated by a Host Controller. The disabled ports must be contiguous,
and must be in decreasing order starting with port 3.
This field is set by the OEM using either the SMBus or EEPROM interface options. When using the
internal default option, the PRT_DIS0 pin will disable the appropriate ports.
5.1.1.15 Dynamic Power
Controls the ability of the 3-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
3-port Hub will always switch to Self-Powered operation.}
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.
5.1.1.16 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.
5.1.1.17 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.
5.1.1.18 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.
5.1.1.19 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 17 Revision 2.3 (08-27-07)
DATASHEET
5.1.1.20 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.
5.1.1.21 Power-On Timer
Time (in 2ms int ervals) from the time power-on sequence begi ns on a port 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.
5.1.1.22 Power Switching Polarity
The selection of active state “polarity” for the PRTPWR[3:1] pins 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.
5.2 EEPROM Interface
The SMSC Hub can be configured via a 2-wire (I2C) EEPROM. (Please see Figure 4.1, "3-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 Specifica tion for details on I2C bus protocols). The Hub’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 designe r 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 18 SMSC USB2503/USB2503A
DATASHEET
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 2503 2503 Product ID (assigned by Manufacturer).
DID 5:4 2 0000 0000 Device ID (assigned by Manufacturer).
Config Data
Byte 1 6 1 98 1C 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 Max Current f or th is configu r ati on (expre 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 19 Revision 2.3 (08-27-07)
DATASHEET
5.2.3.1 EEPROM Offset 1:0(h) - Vendor ID
5.2.3.2 EEPROM Offset 3:2(h) - Product ID
5.2.3.3 EEPROM Offset 5:4(h) - Device ID
5.2.3.4 EEPROM Offset 6(h) - CONFIG_BYTE_1
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.
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 PORT_IND Port Indicator Support: Indicates implementation of LED indicators
0 = No LED indicators.
1 = LED indicators.
5 HS_DISABLE High Speed Disable: Disables the capability to attach as either a High/Full-
speed device, and forces attachment as Full-speed only i.e. (no High -Speed
support).
0 = High-/Full-Speed. (Default)
1 = Full-Speed-Only (High-Speed disabled!)
4 MTT_ENABLE Multi-TT enable: Enables one transaction translator per port operation.
0 = single TT for all ports.
1 = one TT per port (multiple TT’s supported)
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 20 SMSC USB2503/USB2503A
DATASHEET
5.2.3.5 EEPROM Offset 7(h) - CONFIG_BYTE_2
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 on a port-by-port
basis, or ganged.
00 = Ganged sensing (all ports together). (Default for self-power)
01 = Individual port-by-port.
1x = Over current sensing not supported. (may be used with Bus-Powered
configurations only!, and is the default for bus-power)
0 PORT_PWR Port Power Switching: Indicates whether port power switching is on a port-
by-port basis or ganged.
0 = Ganged switching (all ports together)
1 = Individual port-by-port switching.
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
5:4 OC_TIMER OverCurrent Timer: Over Current Timer delay.
00 = 0.1ms
01 = 2ms (Default)
10 = 4ms
11 = 6 ms
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 21 Revision 2.3 (08-27-07)
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
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved
Bit 3= 1; Port 3 non-removable.
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved.
Bit 3= 1; Port 3 is disabled.
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved.
Bit 3= 1; Port 3 is disabled.
Bit 2= 1; Port 2 is disabled.
Bit 1= 1; Port 1 is disabled.
Bit 0 is Reserved, always = ‘0’
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 22 SMSC USB2503/USB2503A
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 Ma x 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 23 Revision 2.3 (08-27-07)
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 24. 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 25.
5.3.1 Bus Protocols
Typical Write Byte and Re ad Byte protocols are shown below. Re gister 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 Ma x 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: T he length of time that is 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 24 SMSC USB2503/USB2503A
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 written 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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 25 Revision 2.3 (08-27-07)
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 t he SMBus 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 VIDM76543210
03h R/W PID LSB PIDL 7 6 5 4 3 2 1 0
04hR/WPID MSB PIDM76543210
05h R/W DID LSB DIDL 7 6 5 4 3 2 1 0
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 NRD 7 6 5 4 3 2 1 0
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 26 SMSC USB2503/USB2503A
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 extern al SMBus host sets this bit after the Hub’s i nternal
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)
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 27 Revision 2.3 (08-27-07)
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 PORT_IND Port Indicator Support: Indicates implementation of LED indicators
0 = No LED indicators.
1 = LED indicators.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 28 SMSC USB2503/USB2503A
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 forces attachment as Full-speed only i.e. (no High -Speed
support).
0 = High-/Full-Speed.
1 = Full-Speed-Only (High-Speed disabled!)
4 MTT_ENABLE Multi-TT enable: Enables one transaction translator per port operation.
0 = single TT for all ports.
1 = one TT per port (multiple TT’s supported)
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 is on a port-by-port
basis, or ganged.
00 = Ganged sensing (all ports together).
01 = Individual port-by-port.
1x = Over current sensing not supported. (must only be used with Bus-
Powered configurations!)
0 PORT_PWR Port Power Switching: Indicates whether port power switching is on a port-
by-port basis or ganged.
0 = Ganged switching (all ports together)
1 = Individual port-by-port switching.
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 ms
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 29 Revision 2.3 (08-27-07)
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= 1; Reserved .
Bit 3= 1; Port 3 non-removable.
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved1
Bit 3= 1; Port 3 is disabled.
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= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved1
Bit 3= 1; Port 3 is disabled.
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 30 SMSC USB2503/USB2503A
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)
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 Ma x 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 Ma x 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 31 Revision 2.3 (08-27-07)
DATASHEET
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.
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 configured via its internal default configuration. (please see Chapter 3, Pin
Configuration 3-Port Hub for specific details on how to enable default configuration.
Please refer to Table 5 .1 on page 18 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, "3-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 18 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.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 POWER_ON_TIME Power On Time: The le ngth 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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 32 SMSC USB2503/USB2503A
DATASHEET
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.
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).
HUB
50K
Strap Low
GR2
50K
Strap High
GR1
+V
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 33 Revision 2.3 (08-27-07)
DATASHEET
5.6.1.1 RESET_N for Strapping Option Configuration
Figure 5.2 Reset_N Timing for Default/Strap Option 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 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.
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
t6 Host acknowledges attach and signals USB
Reset. 100 msec
t7 USB Idle. undefined msec
t8 Complet ion t ime f or requests (with or wit hou t data
stage). 5msec
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 34 SMSC USB2503/USB2503A
DATASHEET
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.
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 5.6 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 Complet ion t ime f or requests (with or wit hou t data
stage). 5msec
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 35 Revision 2.3 (08-27-07)
DATASHEET
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.
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[4:1] to all downstream ports.
4. Clears all TT buffers.
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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 36 SMSC USB2503/USB2503A
DATASHEET
5. Moves device from suspended to active (if suspended).
6. Complies with Section 11.10 of the USB 2.0 Specificati on for behavior after completion of the reset
sequence.
The Host then configu res the Hub and the Hub’s downstream port devices in accordance wi th the USB
Specification.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 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, TEST1, Power, and Gro und). This functionality is enable d by driving TEST1
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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 38 SMSC USB2503/USB2503A
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 ou tp 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 -0.5 2.5 V
3.3V supply
voltage VDDA33
VDDA33PLL
VDD33CR
-0.5 4.0 V
V oltage on any
I/O pin -0.5 (3.3V supply voltage + 2) ≤ 6V
Voltage on
XTAL1 -0.5 4.0 V
Voltage on
XTAL2 -0.5 VDD18 + 0.3V V
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 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 1.71 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 3.3V supply 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
+26
-10
0.8
+72
+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
-22
0.8
-10
-82
V
V
uA
uA
TTL Levels
VIN = 0
VIN = VDD33CR
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 40 SMSC USB2503/USB2503A
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
O12 and I/O12 Type Buffer
Low Output Level
High Output Level
Output Leakage
VOL
VOH
IOL
2.4
0.4
+10
V
V
uA
IOL = 12mA @ VDD33CR = 3.3V
IOH = -4mA @ VDD33C R = 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 100
95 mA
mA
Supply Current
Configured
(High-Speed Host)
2 Ports @ FS/LS
2 Ports @ HS
1 Port HS, 1 Port FS/LS
3 Ports @ HS
IHCC2
IHCH2
IHCH1C1
IHCH3
190
235
215
265
mA
mA
mA
mA
Total from all supplies
Table 7.1 DC Electrical Characteristics (continued)
PARAMETER SYMBOL MIN TYP MAX UNITS COMMENTS
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
SMSC USB2503/USB2503A 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
Configured
(Full-Speed Host)
1 Port
2 Ports
3 Ports
IFCC1
IFCC2
IFCC3
150
155
160
mA
mA
mA
Total from all supplies
Supply Current
Suspend ICSBY 265 uA Total from all supplies.
Supply Current
Reset IRST 150 uA Total from all supplies.
LIMITS
PARAMETER SYMBOL MIN TYP MAX UNIT TEST CONDITION
Clock Input
Capacitance CIN 12 pF All pins except USB pins (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
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 42 SMSC USB2503/USB2503A
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.
Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 43 SMSC USB2503/USB2503A
DATASHEET
Chapter 9 Package Outline
Figure 9.1 48 Pin QFN Package Outline (7x7 mm body - 0.5 mm pitch)
Notes:
1. Controlling Unit: millimeter.
2. Dimension b applies to plated terminals and is measured between 0.15mm and 0.30mm from the
terminal tip. Tolerance on the true position of the terminal is ± 0.05 mm at maximum material
conditions (MMC).
3. Details of terminal #1 identifier are optional but must be located within the zone indicated.
4. Coplanarity zone applies to exposed pad and terminals.
Table 9.1 48 Pin QFN Package Parameters
MIN NOMINAL MAX REMARKS
A 0.70 ~ 1.00 Overall Package Height
A1 0 0.02 0.05 Standoff
A2 ~ ~ 0.80 Mold Thickness
D 6.85 7.00 7.15 X Overall Size
D1 6.55 ~ 6.95 X Mold Cap Size
D2 2.25 ~ 5.60 X exposed Pad Size
E 6.85 7.00 7.15 Y Overall Size
E1 6.55 ~ 6.95 Y Mold Cap Size
E2 2.25 ~ 5.60 Y exposed Pad Size
L 0.30 ~ 0.50 Terminal Length
e 0.50 Basic Terminal Pitch
b 0.18 ~ 0.30 Terminal Width
ccc ~ ~ 0.08 Coplanarity
