The TO-220FP full-pack package provides electrical isolation between the tab and the heat sink — no insulating pad needed, but the thermal path is through the plastic body, so derate the power dissipation accordingly.
At 480 mOhm max at 10 V gate drive, the STF11N65M5 sits in the mid-range for a 650 V 9 A MOSFET — not the lowest Rds(on) in the class, but the 17 nC gate charge is notably light. That combination suits designs where the gate driver is limited in peak current or where switching frequency pushes 100 kHz and above. The input capacitance of 644 pF at 100 V Vds confirms a small Miller plateau, which helps keep switching losses in check. For a flyback primary switch or a PFC boost stage running at 65–100 kHz, the drive burden is low enough that a simple driver IC or even a logic-level gate drive from a controller can handle it.
TO-220FP full-pack — isolation without a pad, but watch the thermal budget
The TO-220FP (full-pack) package has the metal tab fully encapsulated in plastic, so the mounting surface is electrically isolated to the same voltage rating as the die. The 25 W dissipation limit at case temperature is the ceiling — in practice, with the junction rated to 150°C, a heat sink with good airflow is needed to stay below derating at 9 A continuous. The through-hole mounting suits point-to-point wiring on perforated board or traditional PCB layouts where a TO-220 footprint is already established.