200 V P-Channel — high-side switching without a charge pump
The IRF9240 is a P-Channel HEXFET power MOSFET rated for 200 V drain-source and 11 A continuous drain current. A P-Channel device at this voltage class lets you switch the high side of a 200 V rail with a gate drive referenced to the source — no bootstrap or charge-pump circuit needed. That simplifies the gate-drive transformer or isolated supply design in applications like offline flyback converters, motor-drive brake circuits, and high-voltage battery disconnect switches.
580 mOhm on-resistance — conduction loss at 11 A
Rds(on) is specified at 580 mOhm maximum with Vgs=10 V and Id=11 A. At 11 A continuous, the conduction loss is I²R = 70 W — that sets the heatsink requirement. The 125 W package power rating provides headroom, but the junction-to-case thermal path through the TO-220 tab needs a proper heatsink for sustained 11 A operation. The gate threshold is 4 V maximum at 250 µA, so a 10 V gate drive ensures the device is fully enhanced.
60 nC gate charge — driver budget
Total gate charge is 60 nC at Vgs=10 V. For a 100 kHz switching frequency, the average gate-drive current is Qg × f = 6 mA — well within the capability of a standard gate-driver IC. The gate-source voltage is rated ±20 V, so the driver output must not overshoot beyond that absolute maximum during turn-on ringing.
The through-hole TO-220 package suits point-to-point wiring, terminal blocks, and high-reliability solder joints in industrial power stages.
The -55°C floor covers avionics cold-soak and outdoor telecom winter extremes; the 150°C ceiling allows the junction to rise above the case temperature under full load without immediate derating. The 125 W power dissipation rating assumes the case is held at 25°C — real-world derating follows the thermal resistance of the heatsink assembly.