650 V CoolMOS — the PFC and flyback workhorse
The Infineon SPW20N60C3FKSA1 is a 650 V N-channel CoolMOS power MOSFET in the TO-247-3 through-hole package. The 20.7 A continuous drain rating at 25°C case temperature gives you headroom above the typical 10-15 A operating point in a 1-2 kW supply, and the 208 W max dissipation tells you the package can shed the heat if you bolt it to a decent heatsink.
114 nC gate charge — sizing the driver
Gate charge Qg is 114 nC at 10 V. At a 100 kHz switching frequency the average gate-drive current is about 11.4 mA — a standard gate-drive IC like the IR2110 or a bootstrap driver handles that without breaking a sweat. Push the frequency to 200 kHz and the driver's thermal budget and the bootstrap capacitor sizing become the next thing to check. The 2400 pF input capacitance at 25 V Vds is moderate for a 650 V part of this current class; the driver sees a capacitive load that rises as the drain voltage falls during the Miller plateau, but the 114 nC total charge is the number to use for the switching loss calculation.
It's a natural fit for avionics power supplies, satellite DC-DC converters, and downhole instrumentation where the ambient can swing from a cold soak to a hot wellbore. The 150°C Tj(max) is the hard thermal limit — the Rds(on) roughly doubles from 25°C to 150°C, so the conduction loss at the hot end is the real derating constraint.
Active lifecycle — no obsolescence clock ticking
No last-time-buy window to manage, no forced redesign for a replacement. For a production BOM line this means you can commit the quantity without the urgency of an EOL notice. The CoolMOS C3 series has been a staple in power supplies for years; the active status and the through-hole TO-247 package mean this part is still the go-to for designs that need a 650 V, 20 A class switch in a serviceable package.