500 V N-channel in a TO-220 — what it handles
The STP5NK50Z: The 1.5 Ohm maximum Rds(on) at 2.2 A, 10 V gate drive defines the conduction loss for a typical offline flyback primary or a 500 VDC bus switch.
Total gate charge is 28 nC at 10 V, with a ±30 V maximum gate-source rating that leaves headroom for gate-drive overshoot on a 12 V or 15 V rail. Input capacitance Ciss is 535 pF at 25 V drain-source, which together with the gate charge sets the drive current needed for the target switching frequency — a 28 nC gate at 100 kHz draws 2.8 mA average from the driver, well within a standard MOSFET driver's capability.
The TO-220 through-hole package (TO-220-3) allows direct heatsink mounting with a screw or clip — the 70 W maximum power dissipation assumes an infinite heatsink at 25°C case temperature.