P-channel high-side switch — 55 V, 42 A, 20 mOhm
The IRF4905STRLPBF: P-Channel MOSFET, 55 V Vdss, 42 A continuous drain, 20 mOhm Rds(on) at 10 V.
Total gate charge is 180 nC at 10 V. Input capacitance is 3500 pF at 25 V.
Thermal budget — 170 W at the case
Maximum power dissipation is 170 W at Tc=25 °C, derating to zero at 150 °C junction. For continuous 42 A operation, the case temperature must stay below 100 °C to keep the junction under 150 °C at full load; that typically requires a heatsink on the tab or a thermal via array to an internal plane. The -55 to 150 °C junction range covers military and industrial environments, but the thermal interface is the practical limit.