3 A, 400 V fast recovery diode for PFC and boost stages
The STTH3R04RL is a 400 V, 3 A fast recovery rectifier from STMicroelectronics, part of the STTH3 series. Rated for a 175 °C maximum junction temperature, this diode can sit on the same heatsink as a hot MOSFET in a cramped PFC stage without derating the load current. The 1.5 V forward drop at 3 A means 4.5 W conduction loss at full load — the DO-201AD body and lead length must be thermally coupled to the PCB copper or a clip-on heatsink.
Reverse recovery and switching loss trade-off
The 35 ns trr is specified at typical test conditions (IF=3 A, di/dt=100 A/µs). In a 100 kHz CCM PFC, this recovery charge contributes roughly 10–15 % of the total MOSFET turn-on loss — low enough that a standard ultrafast driver can handle it without excessive snubbing. The 5 µA reverse leakage at 400 V and 25 °C rises with junction temperature but stays under control up to the 175 °C limit. Compare this to a standard recovery diode in the same package: the STTH3R04RL's 35 ns trr lets it operate at switching frequencies above 50 kHz where a 200 ns part would overheat the junction from recovery losses alone.
Active production, ROHS3, through-hole package
STMicroelectronics lists the STTH3R04RL as Active with no end-of-life notice. ROHS3 compliant (exemption-free), it ships in tape-and-reel or cut-tape for through-hole insertion. The DO-201AD axial package requires lead forming for PCB mounting — the body diameter is standard for 3 A axial diodes, so existing PTH footprints accept it without a layout change.