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STMicroelectronics STTH20R04FP — Discrete Semiconductors

STTH20R04FP Fast Recovery Diode, 400V 20A TO-220FPAC

MPNSTTH20R04FP
Obsolete

STMicroelectronics STTH20R04FP, Fast Recovery Diode, 400 V DC reverse voltage, 20 A average rectified current, 45 ns reverse recovery time, 1.7 V forward drop at 20 A, TO-220-2 Full Pack (TO-220FPAC), Through Hole mounting.

$1.9200Ref. price · indicative, final on quote
STMicroelectronics STTH20R04FP datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

STTH20R04FP specifications
ParameterValue
MountingThrough Hole
Voltage - DC reverse (Vr)400 V
Voltage - forward (Vf) (Max) @ if1.7 V @ 20 A
Current - reverse leakage @ vr20 µA @ 400 V
Current - average rectified20A
Operating temperature - junction175°C (Max)
SpeedFast Recovery =< 500ns, > 200mA (Io)
PackageTube
TechnologyStandard
CaseTO-220-2 Full Pack
Reverse recovery time45 ns

Product details

The STTH20R04FP is a 400 V, 20 A fast recovery diode from STMicroelectronics, built with standard planar technology and housed in a TO-220-2 Full Pack (TO-220FPAC) through-hole package. Its 45 ns reverse recovery time places it in the ultrafast class for a 400 V part, which matters when you are cleaning up the switching node in a continuous-conduction-mode PFC boost stage or as the output rectifier in a 200–400 W flyback converter. The 45 ns trr means the diode exits conduction fast enough that the MOSFET's body diode does not take over during the dead-time — a common failure mode in hard-switched bridges that shows up as a hot MOSFET and a ringing waveform you cannot snub out.

20 A in TO-220FPAC — the thermal reality

The 20 A average rectified current is the headline number, but the full-pack TO-220FPAC package changes the thermal game. Unlike a standard TO-220 with a metal tab, the full-pack moulding isolates the back — no insulating washer needed when bolting to a grounded heatsink, which simplifies assembly in metal-enclosure designs. The trade-off is higher junction-to-case thermal resistance. At 1.7 V forward drop at 20 A, conduction loss runs 34 W. For pulsed or lower-duty-cycle applications the margin improves.

That means STMicroelectronics has ended production — no last-time-buy window remains open through the factory channel.

Frequently asked questions

Is STTH20R04FP obsolete?

Yes, the STTH20R04FP is listed as Obsolete by STMicroelectronics. Production has ended, and no factory last-time-buy is available.

What is the equivalent of STTH20R04FP?

The STTH20R04FP is a specific full-pack variant (TO-220FPAC) of the STTH20R04 series. A direct functional equivalent in the same series would be the standard TO-220 variant (STTH20R04) or the D²PAK surface-mount variant (STTH20R04D), both of which share the same 400 V, 20 A, 45 ns trr silicon but differ in package and thermal performance. For a newer-design replacement, evaluate ST's current ultrafast diode portfolio at the same voltage and current class.

Does STTH20R04FP require a heatsink?

At its 20 A rated current with a 1.7 V forward drop, conduction loss reaches 34 W. The TO-220FPAC full-pack package has higher thermal resistance than a standard TO-220 tab, so a heatsink is required for continuous operation at or near the rated current to keep the junction temperature within the 175°C maximum. For pulsed or lower-current applications, the thermal margin improves and a heatsink may not be necessary — calculate the junction temperature rise against your duty cycle.