620 V N-channel MOSFET in the I2PAKFP full-pack through-hole package
The STMicroelectronics STFI6N62K3 is a 620 V N-channel power MOSFET from the SuperMESH3™ series, built with a metal-oxide semiconductor structure. Housed in the TO-262-3 Full Pack I²Pak (I2PAKFP, TO-281) through-hole package, the fully isolated tab simplifies heatsinking without an insulating pad — the back of the package is electrically isolated, which matters when you are bolting it to a grounded chassis in an off-line power supply or lighting ballast.
1.2 Ohm Rds(on) and 34 nC gate charge — conduction and switching budget
For a 100 kHz hard-switched converter, budget the gate drive loss at roughly Qg × Vgs × fsw = 34 nC × 10 V × 100 kHz = 34 mW, which is manageable. The 4.5 V gate threshold at 50 µA means the device is fully enhanced only with a 10 V drive — do not expect clean turn-on with 5 V logic.
150°C junction temperature and through-hole mounting
The maximum operating junction temperature is 150°C, which is standard for power MOSFETs. The 30 W power dissipation at the case assumes an infinite heatsink; real designs derate based on the thermal interface. The ±30 V maximum gate-source voltage gives headroom for gate drive transients, but keep the drive voltage at 10 V for the rated Rds(on).