MOSFET power dissipation calculator
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Operating point
Power loss breakdown
Conduction loss
I²·Rds(on)
Switching loss
0.5·V·I·(tr+tf)·f — (tr+tf) ≈ Qg·factor / Ig
Total dissipation
Conduction + switching
Heatsink
Parts above ~1 W need a sink
The device dissipates 1.61 W — above the ~1 W a bare package can shed, so fit a heatsink and size the junction-to-air thermal path for this power.
About the model
Conduction loss is the on-resistance times the drain current squared — Rds(on) rises roughly 50% from 25 °C to 125 °C, so use the hot datasheet value. Switching loss comes from the overlap of voltage and current during each transition; it scales linearly with switching frequency and with gate charge, and shrinks with a stronger gate driver that pushes (tr+tf) down. At high frequency switching loss usually dominates.
The model assumes hard switching with a square-wave drive and no body-diode losses, gate drive losses, or package/thermal derating. Compare against an actual circuit measurement for a production design.
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