1000 V N-channel MOSFET in TO-247-3
The STW5NK100Z is an N-channel MOSFET from ST's SuperMESH3 series, rated for a drain-source voltage of 1000 V and a continuous drain current of 3.5 A at 25°C case temperature. The 3.7 Ohm maximum on-resistance at 1.75 A, 10 V gate drive sets the conduction loss floor for off-line flyback or PFC stages. The TO-247-3 through-hole package handles up to 125 W power dissipation at the case, with the junction temperature range spanning -55°C to 150°C. This suits industrial and automotive auxiliary power supplies where the thermal interface to a heatsink is straightforward.
Input capacitance of 1154 pF at 25 V drain-source sets the switching loss contribution from the Miller plateau. The ±30 V gate-source rating provides margin for ringing on long gate traces.