The STMicroelectronics STD3NK50Z-1 is a 500 V N-channel MOSFET from the SuperMESH series, built with ST's proprietary strip-layout technology that reduces on-resistance per unit area. It delivers a continuous drain current of 2.3 A at the case temperature and features a maximum on-resistance of 3.3 Ohm at 10 V gate drive.
No last-time-buy window remains open through the franchised channel. The IPAK (TO-251) package variant is less common than the DPAK (TO-252) sibling STD3NK50Z, so stock may be thinner. When quoting, confirm date code and traceability; independent stock is typically non-franchised and sold as-is.
The 500 V drain-source voltage rating places this part squarely in offline primary-side switching — flyback, forward, and PFC stages up to about 250 W output. The 2.3 A continuous current is derated from the 45 W power dissipation limit; at 150°C case temperature the usable current drops significantly, so a heatsink or forced airflow is assumed for full-rated output. Gate charge is 15 nC at 10 V, so the gate-drive power requirement is modest; a standard PWM controller with 1 A drive capability switches it cleanly at 60–100 kHz. Input capacitance of 280 pF at 25 V keeps the switching node capacitance low, helping maintain efficiency at higher frequencies.