525 V N-channel in a TO-220FP — what it does
The STF7N52K3: The fully isolated TO-220FP package eliminates the need for a mounting pad or insulator — the tab is electrically isolated, so the screw-down point can share a heatsink with other devices without a separate isolation washer.
Gate charge and switching — 33 nC at 10 V
Total gate charge is 33 nC at a 10 V drive. The input capacitance is 870 pF at 100 V drain-source.
The STF7N52K3 is listed as obsolete.
Thermal budget — 25 W in a TO-220FP
Maximum power dissipation is 25 W at case temperature, but the TO-220FP has a higher thermal resistance than the standard TO-220 because the plastic encapsulation adds a thermal barrier between the die and the heatsink. In practice, for continuous operation at 6 A, the conduction loss alone (I² × Rds(on) at temperature) will eat a large fraction of that 25 W budget — expect to derate the current significantly unless the case is held near 25°C with forced cooling. The 150°C maximum junction temperature is the hard limit; the Rds(on) roughly doubles from 25°C to 150°C, so the thermal loop needs to be calculated at the hot junction, not the 25°C datasheet number.