650 V N-channel MDmesh V MOSFET in TO-3PF full-pack
The STMicroelectronics STFW45N65M5 is an N-channel power MOSFET built on the MDmesh™ V technology, designed for high-voltage switching applications.
Conduction and switching losses — the numbers that matter
The on-resistance is specified at 78 mOhm maximum when driven with 10 V gate voltage at 17.5 A drain current. That 78 mOhm figure is at 25°C junction temperature; at 125°C junction it roughly doubles, so budget conduction loss accordingly for continuous operation. The gate charge totals 82 nC at 10 V, which sets the drive energy per switching cycle and the average gate-drive current needed at the target frequency. Input capacitance measures 3470 pF at 100 V drain-source, a figure that feeds into the switching-time estimate and the driver's peak current requirement.
Thermal and operating limits
Maximum junction temperature is 150°C, and the device is rated for a power dissipation of 57 W at case temperature. The TO-3PF package has a lower thermal mass than a standard TO-247, so the dissipation limit is package-constrained; plan the heatsink and airflow to keep junction temperature under 125°C for reliable long-term operation. The operating temperature limit covers the junction only — storage temperature is not separately stated, but standard handling precautions apply.
For production BOMs, the active status removes last-time-buy risk for new designs.