The STF24NM65N is a 650 V N-channel MOSFET from STMicroelectronics' MDmesh™ II series, built in a through-hole TO-220FP full-pack package. The 650 V Vdss gives 15–20% derating margin on a 400 V DC bus typical of three-phase PFC stages or flyback primary-side clamps.
Gate charge, capacitance, and the driver requirement
Total gate charge is 70 nC at Vgs = 10 V. For a 100 kHz hard-switched converter, this translates to an average gate-drive current of 7 mA plus the peak current needed to charge Ciss (2500 pF at Vds = 50 V) within the desired switching interval. The ±25 V maximum gate rating allows use of standard 12–15 V gate drives without a clamp zener, but the Miller plateau region should be checked against the driver's sink capability to avoid shoot-through. Input capacitance Ciss is 2500 pF at Vds = 50 V — this is moderate for a 650 V device and keeps the driver load manageable for a typical 1–2 A gate-driver IC. The TO-220FP package's isolated tab means no heatsink isolation pad is needed, but the thermal resistance junction-to-case is higher than a standard TO-220, so the 40 W dissipation limit must be respected in the layout.
STMicroelectronics has marked the STF24NM65N as obsolete.
Temperature grade and environment
This suits applications in engine-bay electronics, outdoor telecom rectifiers, and downhole instrumentation where the ambient temperature exceeds the commercial 85°C limit. The threshold voltage Vgs(th) is 4 V maximum at Id = 250 µA, ensuring the device is fully off with a 0 V gate signal across the full temperature range.