800 V, 9 A N-channel in a TO-220FP — what the ratings mean for the BOM
The STF10N80K5 is an 800 V, 9 A N-channel MOSFET from ST's MDmesh™ K5 series, in a TO-220 Full Pack (TO-220FP) through-hole package. The 800 V drain-to-source breakdown voltage gives headroom for a 400 VDC bus with derating for transients — common in auxiliary supplies for three-phase industrial drives and solar inverters.
On-resistance and gate drive
Input capacitance is 635 pF at 100 V drain-source — this sets the Miller plateau charge and the turn-on delay. The ratio of gate charge to input capacitance suggests the device is optimised for fast switching without excessive ringing, typical of the MDmesh K5 series for resonant or quasi-resonant topologies.
Thermal and environmental envelope
The TO-220FP package has a fully isolated metal tab — no insulating pad or washer is needed between the device and the heatsink, which simplifies assembly and reduces thermal resistance to the heatsink compared to a standard TO-220 with a mica insulator.