Automotive high-side switch with 4.5 mOhm Rds(on) — what it handles
The Infineon BTS50045-1TAC is a single-channel high-side N-channel power switch rated for a continuous load current of 23 A with a typical on-resistance of 4.5 mOhm. That Rds(on) figure means the voltage drop across the switch at full load is just over 100 mV — negligible for a 12 V automotive rail, so the load sees nearly the full battery voltage. The part operates over a 3.2 V to 28 V load supply range, covering nominal 12 V and 24 V truck systems as well as cold-crank and load-dump transients. The PG-TO-263-7-8 package (D²Pak with 6 leads plus tab) provides a low-thermal-resistance path to the PCB copper plane for heat sinking.
Fault protection set — what survives and what doesn't
The BTS50045-1TAC integrates over-temperature protection, over-voltage clamping, reverse battery protection, short-circuit protection, and under-voltage lockout (UVLO). Reverse battery protection is built in — if the battery is connected backwards, the switch blocks the reverse current path without damage to the load or the IC. Over-voltage protection handles load-dump events up to 28 V, and the short-circuit protection limits the output current during a fault. The slew-rate controlled turn-on reduces inrush current into capacitive loads, and the integrated load discharge resistor pulls the output to ground when the switch is off.