300 V / 42 A N-channel — primary-side switch or high-voltage DC rail
Gate drive and switching — 90 nC Qg at 10 V
Gate charge is specified at 90 nC typical at 10 V, with a maximum gate-source voltage of ±20 V. Input capacitance is 3200 pF at 25 V drain-source, which together with the gate charge sets the switching speed and driver power loss.
Package and thermal — TO-220, 300 W dissipation
Maximum power dissipation is 300 W at case temperature, and the maximum junction temperature is 175°C. The TO-220 tab is the drain connection; the heatsink pad must be electrically isolated or connected to the drain potential. For high-current designs, the leadframe and PCB traces need to handle the 42 A rating — expect a large copper pour or external bus bar.
The base product number is STP46, and the part is RoHS compliant per ST's standard lead-free finish.