Datasheet

UNIVERSAL SERIAL BUS (USB) APPLICATIONS
HOST/SELF-POWERED AND BUS-POWERED HUBS
TPS2062-1
TPS2065-1
TPS2066-1
www.ti.com ................................................................................................................................................ SLVS714A – FEBRUARY 2007 – REVISED MARCH 2009
The universal serial bus (USB) interface is a 12-Mb/s, or 1.5-Mb/s, multiplexed serial bus designed for
low-to-medium bandwidth PC peripherals (e.g., keyboards, printers, scanners, and mice). The four-wire USB
interface is conceived for dynamic attach-detach (hot plug-unplug) of peripherals. Two lines are provided for
differential data, and two lines are provided for 5-V power distribution.
USB data is a 3.3-V level signal, but power is distributed at 5 V to allow for voltage drops in cases where power
is distributed through more than one hub across long cables. Each function must provide its own regulated 3.3 V
from the 5-V input or its own internal power supply.
The USB specification defines the following five classes of devices, each differentiated by power-consumption
requirements:
• Hosts/self-powered hubs (SPH)
• Bus-powered hubs (BPH)
• Low-power, bus-powered functions
• High-power, bus-powered functions
• Self-powered functions
SPHs and BPHs distribute data and power to downstream functions. The TPS206x-1 has higher current
capability than required by one USB port; so, it can be used on the host side and supplies power to multiple
downstream ports or functions.
Hosts and SPHs have a local power supply that powers the embedded functions and the downstream ports (see
Figure 25 ). This power supply must provide from 5.25 V to 4.75 V to the board side of the downstream
connection under full-load and no-load conditions. Hosts and SPHs are required to have current-limit protection
and must report overcurrent conditions to the USB controller. Typical SPHs are desktop PCs, monitors, printers,
and stand-alone hubs.
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Product Folder Link(s): TPS2062-1 TPS2065-1 TPS2066-1