What the 5.3 mOhm Rds(on) means at the bench
The AUIRFP1405 is an N-channel HEXFET MOSFET in a TO-247 through-hole package, rated for 55 V drain-source and 95 A switching current. The headline figure is the 5.3 mOhm maximum on-resistance at 95 A with 10 V gate drive — that is the conduction loss you pay for in heat every cycle. At full rated current, the dissipation in the channel alone is about 48 W before you account for switching losses, so the 310 W package power rating gives you breathing room for a hard-switched inverter leg.
The ±20 V absolute maximum gate-source rating gives margin for ringing on long gate traces, but a 15 V zener clamp across the gate-source is cheap insurance in a noisy environment.
Temperature grade and where it fits
The junction temperature range is -55°C to 175°C, which is the full automotive-grade band. This part carries the AUTOMOTIVE HEXFET designation — it is qualified for the under-hood thermal cycle and vibration profile. The TO-247 package with through-hole mounting handles the mechanical stress of engine-bay duty better than a surface-mount D²PAK in many cases, and the large backside tab makes heatsinking straightforward with a single M3 screw and thermal compound.