1200 V N-channel MOSFET in the MDmesh K5 family
What the gate charge and capacitance numbers mean for the drive circuit
A gate driver capable of sourcing and sinking at least 1 A will switch the STF12N120K5 cleanly in the 50–100 kHz range. If the switching frequency pushes above 100 kHz, the gate drive losses (Qg × Vgs × fsw) start to become significant in the total power budget.
Temperature range and thermal design
The TO-220FP package has a higher junction-to-case thermal resistance than a standard TO-220 because of the plastic isolation layer — factor that into the heatsink calculation rather than assuming the same thermal performance as a non-isolated TO-220.