60 V, 120 A N-channel HEXFET — the conduction-loss floor
The Infineon IRFB3306PBF is a 60 V, 120 A N-channel power MOSFET from the HEXFET® series, built on planar stripe technology and housed in a TO-220AB through-hole package. It is designed for high-current switching and linear applications where low on-resistance and high junction temperature tolerance are required.
120 nC gate charge — switching-frequency budget
Total gate charge Qg is 120 nC at 10 V. The 4520 pF input capacitance at 50 V drain-source requires a driver capable of high peak current during the Miller plateau. The 4 V gate-threshold maximum at 150 µA drain current means the device is fully enhanced with a 10 V drive, but the threshold spread leaves no headroom for 5 V logic drive — a 10 V rail is required to hit the rated Rds(on).
It is suitable for avionics power supplies, downhole instrumentation, and satellite bus converters where the ambient exceeds the standard 125°C limit of industrial-grade MOSFETs. At 175°C junction, the Rds(on) roughly doubles from the 25°C value — expect about 8.4 mOhm at the hot corner, which must be factored into the thermal design for continuous operation above 125°C.
TO-220AB — through-hole thermal interface
The TO-220AB package provides a metal tab for direct heatsink mounting. The 230 W power dissipation rating at case temperature assumes the tab is bolted to an infinite heatsink — real-world derating follows the junction-to-case thermal resistance, which is not listed here but typically 0.5-0.8 °C/W for this package class. The through-hole mounting suits point-to-point wiring, terminal-block assemblies, and board-level replacement in existing designs where surface-mount reflow is not an option.