USB power switch with adjustable fault protection
It integrates adjustable current limiting, over-voltage protection, over-temperature shutdown, and under-voltage lockout, making it a self-contained power distribution solution for USB ports and general-purpose 5 V rails.
At 3 A load, the 47 mOhm typical on-resistance drops about 141 mV across the switch. That voltage margin must be accounted for in the downstream regulator headroom or USB VBUS tolerance budget. The 16-WQFN (3x3 mm) exposed-pad package sinks the I²R heat to the PCB copper — the thermal pad area on the board sets the actual junction temperature rise above the -40 to 125 °C rated range.
Fault protection set — adjustable current limit, OVP, OTP, UVLO
The TPS2549RTET includes adjustable current limiting (set by an external resistor), over-voltage protection that clamps the output if the input exceeds the safe threshold, over-temperature shutdown that latches off the switch at die overtemperature, and under-voltage lockout that holds the switch off until the supply rail is stable. The status flag output signals fault conditions to the host controller. The load-discharge feature pulls the output to ground when the switch is disabled, preventing a floating VBUS after disconnect.