Low-side switch for rugged loads
The Infineon BSP78HUMA1 is a single-channel low-side N-channel power switch from the HITFET® series, designed for general-purpose on/off switching of resistive, inductive, and lamp loads. It delivers up to 3 A continuous output current with a typical Rds(on) of 35 mOhm, keeping conduction losses low for a 42 V max load supply. The switch operates over a -40°C to 150°C junction temperature range, suiting it for under-hood automotive, industrial actuator, and solenoid-drive environments where ambient heat is high. Integrated fault protection — fixed current limiting, over-temperature shutdown, and over-voltage clamping — lets the part survive short circuits and load dumps without external clamp diodes.
Fault protection — self-contained, no external clamp
Fixed current limiting prevents the output from exceeding safe levels during a short circuit; the part will auto-restart after the fault clears (the Auto Restart feature is listed). Over-temperature protection shuts the switch off if the die exceeds the thermal threshold, and over-voltage clamping absorbs inductive flyback energy from relays or solenoids. For a typical automotive load like a fuel pump or cooling fan, this eliminates the need for a freewheeling diode across the load, saving board space and BOM cost.
Package and mounting
The BSP78HUMA1 is supplied in a PG-SOT223-4 package (TO-261-4 equivalent), a surface-mount footprint with a large tab for heat transfer to the PCB.
Lifecycle and sourcing
The BSP78HUMA1 is an active, current-production part per Infineon's lifecycle status. The part is ROHS3 compliant. For BOM planning, this means no near-term LTB risk; the part can be specified into new designs with confidence.