55 V, 51 A N-channel power switch — where the Rds(on) matters
The IRFZ44ZPBF is a 55 V, 51 A N-channel MOSFET from Infineon's HEXFET® series, housed in a through-hole TO-220-3 package. The headline numbers — 55 V drain-to-source and 51 A continuous drain at 25°C case temperature — place it in the medium-voltage power-switching class, suited for DC motor drives, battery management, and DC-DC converter primary switches where the rail sits at 12 V, 24 V, or 48 V.
Switching-speed parametrics and gate-drive budget
These numbers set the switching-speed ceiling: a gate driver sourcing 1 A charges the gate in about 43 ns, but the Miller plateau and output capacitance (not listed) extend the actual switching interval.
The IRFZ44ZPBF carries a Not Recommended for New Designs (NRND) status from Infineon. This means the part is still available for existing production but is not qualified for new design-ins. For a BOM line already using this MOSFET, the NRND flag signals that a last-time-buy window may open — sourcing through independent distribution against an RFQ is the practical path for sustaining production.
Through-hole TO-220 — board and thermal integration
The tab is electrically common with the drain — an insulating pad and thermal grease are required if the heatsink is grounded. The 80 W power dissipation at the case assumes the tab is held at 25°C; in practice, the junction-to-case thermal resistance (not listed) and the heatsink's thermal resistance set the real power limit.