The headline on-resistance is 1.35 mOhm maximum at Vgs = 10 V and Id = 20 A — this is the figure that sets the conduction loss in a synchronous buck or load switch. Total gate charge is 55 nC at Vgs = 10 V, which tells the drive stage how much current it needs to hit the target switching frequency.
Thermal and current headroom — the two current ratings
The 31 A Ta rating assumes free-air convection on a standard PCB footprint; the 205 A Tc rating requires a heatsink or thermal pad tied to a large copper plane, because the package alone cannot shed that heat. Maximum power dissipation is 2.5 W at ambient (Ta) and 107 W at case temperature (Tc) — the junction-to-case thermal path is the limiting factor for sustained high-current operation.