Automotive fast-recovery rectifier for 400 V rails
The STTH1R04AY is an automotive-grade (AEC-Q101) 400 V, 1 A fast-recovery rectifier from STMicroelectronics, in a DO-214AC (SMA) surface-mount package. Its 30 ns reverse recovery time and 175°C maximum junction temperature suit it for switching power supplies, DC-DC converters, and snubber circuits in under-hood automotive electronics.
A 30 ns reverse recovery time at 400 V, 1 A keeps switching losses low in hard-switched topologies like boost PFC stages and flyback converters. The fast recovery reduces the reverse-recovery charge that the MOSFET or IGBT must absorb, which directly lowers the device junction temperature and improves efficiency. Forward voltage is specified at 1.6 V maximum at 1 A, giving a conduction loss floor of 1.6 W at full rated current. Reverse leakage is 5 µA at 400 V, which rises with junction temperature — at 175°C the leakage contribution to the thermal budget becomes significant and should be factored into the heatsink design.
175°C junction — under-hood thermal margin
The 175°C Tj max provides derating headroom for high-frequency switching applications where self-heating adds to the ambient.