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.