The STTH30R04WY from STMicroelectronics is an automotive-grade fast recovery diode rated for 400 V reverse voltage and 30 A average forward current, housed in a DO-247 through-hole package. It is qualified to AEC-Q101, meaning it has passed the semiconductor stress tests required for automotive applications such as engine control units, transmission modules, and on-board chargers. The 100 ns reverse recovery time (trr) places it in the fast recovery class, making it suitable for high-frequency rectification in boost PFC stages, output rectifiers in DC-DC converters, and snubber clamp circuits where switching losses and EMI matter.
Ratings that drive the design
The 400 V blocking voltage (Vr) and 30 A average current (Io) define the power envelope: this diode can handle up to 400 V in reverse bias and conduct 30 A continuously. The 100 ns trr is the headline switching parameter: in a 100 kHz PFC stage, that recovery speed keeps turn-off losses manageable and limits ringing without excessive snubbing. Reverse leakage is specified at 15 µA at 400 V, a typical figure for this voltage class.
The DO-247 package has a large metal tab for heatsinking. The tab is electrically common with the cathode, so an insulating pad or thermal compound is needed if the heatsink is grounded.
Lifecycle reality
Buyers should verify date codes and request traceability when sourcing from independent channels, as obsolete parts carry a higher risk of counterfeit or refurbished material.