TUSB2077A,pdf(7-Port Hub for t

The TUSB2077A hub is a 3.3-V CMOS device that provides up to seven downstream ports in compliance with the USB version 1.1 specification. Because this device is implemented with a digital state machine instead of a microcontroller, no software programming is required. Fully-compliant USB transceivers are integrated into the ASIC for all upstream and downstream ports. The downstream ports support both full-speed and low-speed devices by automatically setting the slew rate according to the speed of the device attached to the ports. The configuration of the BUSPWR terminal selects either the bus-powered or self-powered mode. The introduction of the DP0 pullup resistor disable terminal, DP0PUR, makes it much easier to implement an onboard bus/self-power dynamic-switching circuitry.