STP20NK50Z - STW20NK50Z is a N-channel 500V - 0.23Ω - 20A TO-220/TO-247 Zener-Protected SuperMESH™Power MOSFET from ST company, which features typical RDS(on) = 0.23 Ω, extremely high dv/dt capability, 100% Avalanche tested, minimized gate charge, very low intrinsic capacitances and very good manufacturing repeatability.