1050 V N-channel MOSFET in a TO-3PF full-pack
The STMicroelectronics STFW2N105K5 is an N-channel MOSFET from the SuperMESH5™ series, built for high-voltage switching applications. The full-pack isolation simplifies heatsinking — no insulating washer needed between the tab and the heatsink, which cuts assembly time and thermal resistance in the mounting stack. The SuperMESH5™ process targets low gate charge (10 nC typical at 10 V) to keep switching losses manageable in hard-switched topologies like flyback or PFC stages.
The 8 Ohm maximum Rds(on) is specified at 750 mA drain current with 10 V gate drive. That 8 Ohm at 2 A means 32 W conduction loss at full current — well above the 30 W package dissipation limit, so the design must operate well below the continuous rating or use pulse duty. For a flyback primary switch at 100 kHz, the 10 nC gate charge draws only 1 mA average from the gate driver, so a simple driver IC or even a discrete totem-pole will handle it. Vgs(th) is 5 V maximum at 100 µA drain current, which is a relatively high threshold. This means the device is fully off with a 0 V gate signal even in noisy environments, but the gate drive must swing cleanly above 10 V to achieve the rated Rds(on). A 12 V or 15 V gate supply is typical.
Sourcing and lifecycle posture
It is ROHS3 compliant.