1.1 mOhm at 50 A — the conduction-loss floor
The IRFH8303TRPBF is an N-channel MOSFET from Infineon's HEXFET® and StrongIRFET™ series, built for low-voltage, high-current switching. At 50 A the dissipation in the channel is under 3 W, which keeps the junction within the -55°C to 150°C operating range even without aggressive heatsinking, provided the PCB copper area under the 8-PowerTDFN package is adequate.
Dual current rating — Ta vs Tc
The continuous drain current is rated at 43 A at 25°C ambient (Ta) and 100 A at 25°C case temperature (Tc). The Ta figure assumes free-air convection on a standard footprint; the Tc figure reflects the silicon limit when the package backside is soldered to a large copper plane or heatsink. For a 50 A rail, the design can stay within the Ta rating with good layout, but for the full 100 A capability the board must pull heat from the PQFN's exposed pad.
Gate charge and drive voltage
Total gate charge at 10 V is 179 nC. That is a moderate figure for a 100 A FET — the gate driver needs to source about 1.8 A peak to switch in 100 ns.