The STP8NM50N is an STMicroelectronics N-channel power MOSFET from the MDmesh™ II family, built for high-voltage switching in the 500 V class.
The input capacitance of 364 pF at 50 V drain-source is low enough that the gate waveform stays clean with a standard 10 Ω to 22 Ω gate resistor, but the 150°C junction temperature rating means the thermal design must handle the sum of conduction and switching losses at full load.
The MDmesh II platform has been a workhorse for years, so the risk of a surprise EOL in the next procurement cycle is low — but as with any active part, the buyer should confirm current lead times and pricing at quote time.