The STP5NK90Z is an STMicroelectronics N-channel power MOSFET built on the SuperMESH technology platform. The 41.5 nC typical gate charge keeps switching losses manageable in hard-switched topologies. This part is aimed at high-voltage offline power supplies, flyback converters, PFC stages, and industrial inverter circuits where the 900 V breakdown gives headroom for rectified 400 VDC rails plus surge margin. The TO-220 package makes it a straightforward through-hole replacement on existing boards — no special reflow profile needed, just a heatsink and a screwdriver.
The STP5NK90Z is marked obsolete by STMicroelectronics. That means no further factory orders are accepted — no last-time-buy window remains open. We source it on a quoted-to-order basis against an RFQ, confirming availability and current pricing at quote time.
Ratings that drive the fit decision
The 900 V Vdss is the headline number — it sets the part for offline AC-DC converters where the bulk rail sits around 400 VDC and you need 800 V to 900 V rating for reliable avalanche and surge withstand. The 2.5 Ohm Rds(on) at 10 V gate drive is the conduction loss anchor — at 2.25 A that is about 11.4 W conduction loss, which against the 125 W package limit leaves thermal margin for switching losses.