3
SLVSDC2B – FEBRUARY 2016 – REVISED AUGUST 2016
Product Folder Links:
Copyright © 2016, Texas Instruments Incorporated
5 Description (continued)
The port-power switch provides up to 3 A downstream at 5 V for legacy and Type-C USB power. An additional
bidirectional switch path provides USB PD power up to 3 A at a maximum of 20 V as either a source (host), sink
(device), or source-sink.
The TPS65981 device is also an upstream-facing port (UFP), downstream-facing port (DFP), or dual-role port for
data. The port-data multiplexer passes data to or from the top or bottom D+/D– signal pair at the port for USB 2.0
HS and has a USB 2.0 low-speed endpoint. Additionally, the sideband-use (SBU) signal pair is used for auxiliary
or alternate modes of communication (DisplayPort, for example).
The power-management circuitry uses 3.3 V inside the system and also uses VBUS to start up and negotiate
power for a dead-battery or no-battery condition.