55 V, 69 A N-channel HEXFET — the bench-level view
The AUIRFZ48N is an Infineon N-channel HEXFET MOSFET in a TO-220 through-hole package, rated for 55 V drain-source and 69 A continuous drain current. Its 14 mOhm on-resistance at 40 A with 10 V gate drive makes it a solid choice for motor-drive outputs, battery-switch rails, and DC-DC converters where the junction temperature can hit 175°C.
At 40 A load, the dissipation is roughly 22 W — the TO-220 copper tab area and airflow determine whether a heatsink is needed. Gate charge is 63 nC at 10 V. For a 100 kHz hard-switched converter, the driver must supply about 6.3 mA average; a standard gate-driver IC with 1 A peak handles it easily. The ±20 V Vgs max gives margin for gate-drive overshoot.
Package and temperature grade
Through-hole TO-220 package — the tab is the drain. Junction temperature range is -55°C to 175°C, which covers automotive under-hood and industrial motor-drive environments where the die sees sustained thermal cycling.