30 ns trr — the switching-speed anchor for automotive PFC and DC-DC
The STTH4R02UY is an STMicroelectronics automotive-grade fast-recovery epitaxial diode, rated 200 V reverse and 4 A average forward current, with a 30 ns reverse recovery time that places it in the ultrafast class for a 200 V part. It is specified for continuous conduction mode (CCM) power factor correction stages, output rectification in DC-DC converters, and freewheeling paths in automotive inverter and motor-drive circuits where the 175°C junction temperature rating allows placement near the engine bay or transmission without thermal derating.
4 A forward, 1.05 V Vf — conduction loss and the SMB thermal budget
At 4 A forward current the maximum forward voltage is 1.05 V, producing a conduction loss of 4.2 W at the peak rated current. The SMB (DO-214AA) package relies on the PCB copper pad area under the cathode tab for heat spreading; a 1 oz copper pour of at least 30 mm² per terminal keeps the junction temperature within the -40°C to 175°C operating range at full load. Reverse leakage is 3 µA at 200 V, which does not materially affect the thermal budget at high line.
Automotive qualification and active lifecycle
The STTH4R02UY carries an Automotive grade designation, consistent with AEC-Q101 qualification for stress-tested semiconductor devices used in under-hood and chassis-domain power electronics.
Package and footprint — SMB (DO-214AA) surface mount
The diode is supplied in the SMB (DO-214AA) package, a surface-mount outline with a 0.50 mm lead pitch and a body size that fits standard 8 mm tape. The cathode is marked by a band on the body; the anode is the smaller terminal. The SMB footprint is shared with many 2 A to 5 A rectifiers, so the STTH4R02UY can be a drop-in replacement for existing SMB fast-recovery diodes in the same voltage and current class, provided the trr and Vf match the circuit timing and loss budget.