USB host-port power switch — 73 mOhm, 2.5 A, in a 3x3 mm QFN
Its 73 mOhm typical on-resistance at 5 V sets the voltage drop to the connector: at 2.5 A that's about 180 mV of IR drop before the cable, so the host-side regulation must account for it. The part integrates adjustable current limiting, over-temperature protection, and UVLO — the protection suite that keeps the 5 V bus from collapsing under a short or a hot plug.
2.5 A output and junction-temperature derating
The catch: the 73 mOhm Rds(on) at 25°C roughly doubles at 125°C junction, so the actual IR drop and self-heating at 2.5 A will be higher than a room-temperature calculation suggests.
Protection features and interface
The switch is controlled by a single On/Off logic input with a non-inverting input type, and it outputs a status flag that can signal a fault to the host controller. The fault protection set includes adjustable current limiting (set with an external resistor), over-temperature shutdown, and UVLO — the UVLO threshold ensures the switch turns off cleanly if the 5 V rail droops below the regulation window. The output configuration is high-side N-channel, so the load is switched on the positive rail and the ground path is continuous.