Automotive USB power switch with integrated fault protection
It delivers up to 3 A continuous from a 4.5 V to 6.5 V load supply, with a typical on-resistance of 45 mOhm. The switch integrates adjustable current limiting, over-temperature protection, over-voltage protection, and under-voltage lockout (UVLO), plus a status flag output. The non-inverting On/Off interface and 1:1 input-to-output ratio make it a straightforward drop-in for USB port power control in infotainment, telematics, and body-control modules.
At 3 A load, the 45 mOhm typical on-resistance produces about 135 mV drop and 405 mW dissipation inside the 20-WQFN package. The adjustable current limit lets you set the trip point below the 3 A ceiling to protect the upstream regulator or wiring harness — the datasheet's application section shows the resistor value calculation.
Fault protection set covers the common USB failure modes
Over-voltage protection clamps the output if the load supply exceeds the safe operating area — relevant when a USB port is exposed to a miswired or jumped battery line. The adjustable current limit handles a shorted cable or a downstream fault without tripping the vehicle's fuse. UVLO holds the switch off until the input rail is above the threshold, preventing partial turn-on during a cold-crank event. Over-temperature shutdown protects against a stalled fan or blocked airflow in a sealed ECU enclosure.
Package and mounting — 20-WQFN with exposed pad
The 20-WFQFN exposed-pad package (4x3 mm body) requires a thermal land pattern on the PCB with via stitching to the ground plane. The supplier device package designation is 20-WQFN (4x3).
The base product number is TPS254900. For a BOM line requiring AEC-Q100 qualification and a known-good automotive USB switch, this part is a current-production choice with no near-term obsolescence risk.