650 V N-channel MOSFET in TO-220 — STP21N65M5
Gate drive and switching behaviour
The STP21N65M5 requires a 10 V gate drive to achieve the specified 190 mOhm Rds(on). Gate charge is 50 nC at 10 V, which is moderate for a 650 V device in this current class — a standard gate-driver IC with 1 A to 2 A peak output will switch it cleanly at frequencies typical of hard-switched PFC stages. Input capacitance measures 1950 pF at 100 V drain-source bias, giving a reasonable Miller plateau for designers to budget dead-time and cross-conduction margins.
Thermal and package considerations
Maximum power dissipation is 125 W at case temperature, and the junction temperature rating is 150 °C. The TO-220 package with a metal tab is intended for heatsink mounting — without a heatsink, the continuous current must be derated significantly. The through-hole form factor suits point-of-load and bulk-capacitor layouts where a surface-mount part would complicate thermal management.