1FEATURES

2• 2.8 V to 19.8 V

• Auto Selects 3.3 V Supply

• > 10-mA Low Power Switch

• > 500-mA High Power Switch

• Reverse Current Blocking From OUT to VDD

• Wake on UART Input Activity

• UART RX and TX Buffers

APPLICATIONS

• Thunderbolt™ Cables

• Notebook Computers

• Desktop Computers

• Power Management Systems

DESCRIPTION

The TPS22985 is a supply selection device for active

Thunderbolt™ cables. The device selects a supply

that is at 3.3V from two supply inputs and connects

this to two non-current limited outputs OUTA and

OUTB. When 3.3V is not present at either supply, the

outputs become high impedance.

The TPS22985 has two modes of operation, Normal

and Control.

In Normal Mode, OUTA is always on when a valid

supply is present. OUTB is connected to a valid VDD

when the ENB input is high.

In Control Mode, OUTA functions the same as

Normal Mode and OUTB is controlled by a

combination of monitored inputs and valid supplies on

VDD1 and VDD2. When a valid VDD is available, the

device waits for a rising input on ENB and then

disconnects OUTB until the next falling RXH

transition. Once the next falling RXH transition

occurs, the device reconnects OUTB.

In either mode, when a valid VDD is not available, the

TPS22985 opens all switches and the outputs OUTA

and OUTB become high impedance. When the

connected VDD exceeds a maximum voltage of 3.6V,

it is disconnected from the outputs. VDD2 will only

connect when it is in the valid range and VDD1 is

greater than 3.6V

The TPS22985 is available in a 1.6mm x 1.6mm

WCSP package.