55 V, 47 A, 22 mΩ — what these ratings mean for your power rail
The 1700 pF input capacitance at 25 V drain bias is moderate; the gate driver sees a 48 nC total gate charge at 5 V, so a 1 A gate driver switches it in under 50 ns.
D2PAK package — thermal and layout considerations
The part comes in a TO-263-3 / D²Pak surface-mount package (2 leads plus tab, TO-263AB). The datasheet quotes 3.8 W dissipation at 25°C ambient (still air) and 110 W at the case — the real number depends on your board's copper thickness, via stitching to an internal plane, and airflow. For continuous 47 A, a 2 oz copper pour of at least 6 cm² per side is a starting point; anything less and the junction will climb past 175°C. Operating junction temperature range is -55°C to 175°C, so it handles engine-bay heat or cold-soak without derating the voltage or current — just watch the Rds(on) increase of about 0.5% per °C above 25°C. At 125°C junction, the 22 mΩ spec roughly doubles to 44 mΩ, which doubles the conduction loss for the same current.
Infineon lists the IRLZ44NSTRRPBF as obsolete. That means this part is no longer in production; any new stock comes from surplus, broker, or last-time-buy inventory.