ISP1123
Universal Serial Bus compound hub
Rev.
01 — 5 October 1999 Preliminary specification
1.
General description
The ISP1123 is a compound Universal Serial Bus (USB) hub device which complies with USB Specification Rev.
1.
1.
It integrates a Serial Interface Engine (SIE), hub repeater, hub controller, USB data transceivers and a 3.
3 V
voltage regulator.
It has a configurable number of downstream ports, ranging from 2 to 5, with one port dedicated to an embedded or non-removable function.
The ISP1123 can be bus-powered, self-powered or hybrid-powered.
When it is hybrid-powered the hub functions are powered by the upstream power supply (VBUS), but the downstream ports are powered by an externa...