900 V N-channel in a TO-247-3
The STW9NK90Z is an N-channel MOSFET from STMicroelectronics' SuperMESH series, rated for 900 V drain-to-source and 8 A continuous drain current at 25°C case temperature. It comes in a through-hole TO-247-3 package, a standard footprint for high-voltage power stages in switched-mode power supplies, PFC boost converters, and flyback topologies. The 1.3 Ohm maximum on-resistance at 10 V gate drive and 3.6 A drain current defines the conduction loss budget for a given load. Gate charge of 72 nC at 10 V sets the switching energy and the drive current requirement from the gate-driver IC.
The 900 V Vdss provides headroom for offline rectified voltages plus switching overshoot. The 8 A continuous rating at case temperature 25°C must be derated for actual heatsink and ambient conditions; the 160 W maximum power dissipation at Tc is the thermal limit the heatsink must stay under. The 1.3 Ohm Rds(on) at 10 V gate drive means the device is fully enhanced with a standard 10 V gate signal — common for MOSFET drivers in SMPS controllers. Input capacitance of 2115 pF at 25 V drain bias is moderate for a 900 V part, keeping the Miller plateau manageable for hard-switched topologies.
It is ROHS3 compliant. No last-time-buy or obsolescence risk is present on the manufacturer's record.