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STMicroelectronics STF21N90K5 — Discrete Semiconductors

STF21N90K5 N-Channel MOSFET, 900V 18.5A TO-220FP

MPNSTF21N90K5
Active

STMicroelectronics SuperMESH5™ STF21N90K5 N-channel MOSFET, 900V Vdss, 18.5A Id, 299 mOhm Rds(on) at 9A, 43 nC gate charge, TO-220FP full-pack through-hole package.

$7.6900Ref. price · indicative, final on quote
PackagingTO-220-3 Full Pack
RoHSROHS3 Compliant
SeriesSuperMESH5™
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

STF21N90K5 specifications
ParameterValue
SeriesSuperMESH5™
FET typeN-Channel
MountingThrough Hole
Drain to source voltage900 V
Drive voltage (Max rds on, min rds on)10V
Current - continuous drain (Id) @ 25°C18.5A (Tc)
Power dissipation40W (Tc)
Operating temperature-55°C ~ 150°C (TJ)
PackageTube
Vgs±30V
TechnologyMOSFET (Metal Oxide)
CaseTO-220-3 Full Pack
Vgs(th) (Max) @ id5V @ 100µA
Rds on (Max) @ id, vgs299mOhm @ 9A, 10V
Gate charge (Qg) (Max) @ vgs43 nC @ 10 V
Input capacitance (Ciss) (Max) @ vds1645 pF @ 100 V

Product details

900 V N-channel in a fully isolated TO-220FP

It comes in a TO-220FP full-pack through-hole package — the moulded plastic body isolates the tab, so you skip the insulating washer and mica pad when bolting it to a heatsink. That saves a few minutes per unit on the assembly line and one less thermal interface to worry about under vibration.

That conduction loss number lands the part in the sweet spot for a 900 V class — low enough to keep the heatsink reasonable, high enough that the die stays small and the gate charge moderate. Gate charge totals 43 nC at 10 V, which means a standard gate-driver IC can switch it without a booster stage. Input capacitance is 1645 pF at 100 V drain-source, so the driver sees a manageable load at moderate frequencies.

Rework note — the full-pack helps

The TO-220FP is a through-hole part, so rework means desoldering the three leads from the board. The fully isolated tab means you can clamp the body in a heatsink or a third-hand without worrying about shorting the drain to the fixture. No separate insulator to lose or mis-seat.

Frequently asked questions

What is the Rds(on) of STF21N90K5?

Maximum on-resistance is 299 mOhm at 9 A drain current with 10 V gate drive. That is the spec at 25°C junction temperature; expect the value to increase with temperature per the normalised curve in the datasheet.

What package does STF21N90K5 come in?

It comes in a TO-220FP full-pack through-hole package. The supplier device package code is TO-220FP — a fully isolated plastic body with three leads.