2007 - 2016 Microchip Technology Inc.
DS000002249A-page 1
Highlights
• Integrated USB 2.0 Compatible 3-Port Hub
- 3 Transaction Translators for highest perfor-
mance
- 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 I
2
C EEPROM
- SMBus Slave Port
• Default VID/PID/DID, allows functionality when
configuration EEPROM is absent
• Hardware Strapping options allow for configura-
tion 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 RoHS compliant package
USB2503/USB2503A
Integrated USB 2.0 Compatible 3-Port Hub
USB2503/USB2503A
DS000002249A-page 2
2007 - 2016 Microchip Technology Inc.
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The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).
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2007 - 2016 Microchip Technology Inc.
DS000002249A-page 3
USB2503/USB2503A
Table of Contents
1.0 Introduction ..................................................................................................................................................................................... 4
2.0 Pin Table 3-Port .............................................................................................................................................................................. 5
3.0 Pin Configuration 3-Port Hub .......................................................................................................................................................... 6
4.0 3-Port Hub Block Diagram .............................................................................................................................................................. 7
5.0 Functional Block Description ......................................................................................................................................................... 12
6.0 XNOR Test .................................................................................................................................................................................... 30
7.0 DC Parameters ............................................................................................................................................................................. 31
8.0 AC Specifications .......................................................................................................................................................................... 34
9.0 Package Outline ............................................................................................................................................................................ 35
Appendix A: Data Sheet Revision History ........................................................................................................................................... 37
The Microchip Web Site ...................................................................................................................................................................... 38
Customer Change Notification Service ............................................................................................................................................... 38
Customer Support ............................................................................................................................................................................... 38
Product Identification System ............................................................................................................................................................. 40
USB2503/USB2503A
DS000002249A-page 4
2007 - 2016 Microchip Technology Inc.
1.0
INTRODUCTION
The Microchip 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 Transaction Translator (TT) is available for each downstream facing port. This architecture ensures maxi-
mum 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 V
BUS
switching to downstream ports,
and to limit current and sense over-current conditions.
All required resistors on the USB ports are integrated into the Hub. This includes all 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 the upstream port, and the down-
stream 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 possible to modify a limited sub-set of the configuration options.
The USB2503/USB2503A may also be configured by an external EEPROM or a microcontroller. When using the micro-
controller interface, the Hub appears as an SMBus slave device. If the Hub is pin-strapped for external EEPROM con-
figuration 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 I
2
C 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 permanently hardwired to a downstream USB peripheral 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
2007 - 2016 Microchip Technology Inc.
DS000002249A-page 5
USB2503/USB2503A
2.0
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/SMBCLK/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)
USB2503/USB2503A
DS000002249A-page 6
2007 - 2016 Microchip Technology Inc.
3.0
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.
VD
D
A
33
1
U
SBDP0
2
USB
DN0
3
VS
S
4
USB
DN1
5
U
SBDP1
6
VD
D
A
33
7
U
SBDP2
8
USB
DN2
9
VS
S
1
0
USB
DN3
11
U
SBDP3
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
CL
KIN_
EN
34
O
C
S1
_N
33
PRT
P
W
R
1
32
O
C
S2
_N
31
VDD
1
8
30
VSS
29
VBU
S_DET
28
SELF_PWR
26
SCL/SM
BC
LK/C
FG_SEL0
25
SDA
/SM
BDA
T
A
27
CFG_SEL1
36
TEST1
MICROCHIP