USB2504-ABZJ SMSC Corporation, USB2504-ABZJ Datasheet - Page 3

• Manufacturer Part Number: USB2504-ABZJ
• Description: INTEGRATED USB2.0 COMPATIBLE 4 - PORT HUB
• Manufacturer: SMSC Corporation

Integrated USB2.0 Compatible 4-Port Hub
General Description
SMSC USB2504/USB2504A
OEM Selectable Features
The SMSC 4-Port Hub is fully compliant with the USB2.0 Specification and will attach to a USB host
as a Full-Speed Hub or as a Full-/High-Speed Hub. The 4-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 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 V
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 downstream facing ports will be called the downstream ports.
A default configuration is available in the USB2504/USB2504A 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 USB2504/USB2504A 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 4-Port Hub supports several OEM selectable features:
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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.
LED indicator support.
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
LED support
MTT enable
Ganged Vs Port power switching and over-current sensing
PRODUCT PREVIEW
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Revision 1.8 (11-11-05)
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