What this PROFET high-side switch does in the power path
The Infineon BTS500402SFAXUMA2 is a dual-channel high-side power switch from the PROFET® family, designed to replace a relay-and-fuse combination with a single IC. It switches a 6 V to 28 V load rail on and off under logic control, and it protects itself and the wiring against over-temperature, over-voltage, and short-circuit faults. Each of the two N-channel output stages is rated for 11 A continuous maximum, and the typical on-resistance is 4 mOhm — low enough that at 11 A the conduction loss is under half a watt per channel at 25 °C junction.
4 mOhm Rds(on) and 11 A — sizing the load and the thermal budget
The 4 mOhm typical Rds(on) is the headline parametric for this switch: at 11 A the I²R loss is 0.48 W per channel, and at a more typical 5 A it drops to 0.1 W. That low dissipation means the PG-DSO-36-12 package can handle the heat without forced airflow in many automotive and industrial enclosures. The slew-rate controlled output limits inrush current into capacitive loads, which reduces the risk of nuisance over-current trips and keeps the supply rail from dipping during turn-on.
The BTS500402SFAXUMA2 is listed as obsolete by Infineon.
Package and footprint — 36-BSSOP with 0.50 mm pitch
The 0.50 mm lead pitch is hand-solderable with a fine tip and good flux, but a hot-air rework station makes the job cleaner.