650 V, 95 mOhm — the switching-loss trade-off
The STF38N65M5 is a 650 V N-channel MOSFET from ST's MDmesh™ V series, built for high-voltage switched-mode power supplies and power conversion stages where conduction loss and switching loss need balancing. The 95 mOhm Rds(on) at 10 V gate drive gives a low conduction-loss floor at 15 A load current, while the 71 nC total gate charge keeps the switching energy per cycle manageable in the 50–150 kHz range typical of LLC resonant converters and PFC stages.
TO-220FP — isolated tab, higher thermal resistance
That simplifies assembly and cuts a BOM line, but the plastic encapsulation adds thermal resistance: the 35 W power dissipation ceiling at case temperature is lower than a standard TO-220 would deliver. The junction-to-case thermal path is the constraint; a 150°C maximum junction temperature means the heatsink must keep the case temperature low enough to stay within the 35 W budget at the actual load current.
The part is ROHS3 compliant.