400 V, 1 A fast recovery in a SMB footprint
The STTH1R04U is a 400 V, 1 A standard recovery diode from STMicroelectronics, packaged in a DO-214AA (SMB) surface-mount case. Its 30 ns reverse recovery time places it in the fast-recovery class (trr ≤ 500 ns at >200 mA), making it suitable for snubber, clamp, and freewheeling circuits in switched-mode power supplies and motor drives where recovery speed governs switching losses.
Parametric profile for the BOM line
Rated 1 A average rectified current at 400 V reverse voltage, with a forward voltage drop of 1.5 V max at 1 A. The 30 ns reverse recovery time means the diode clears stored charge fast enough to keep the switching node clean in a 100 kHz PFC boost stage — the recovery loss scales with trr × fsw × Vr, so a 30 ns part at 400 V and 100 kHz dissipates roughly 1.2 W in recovery alone, which the SMB package can handle with adequate copper on the cathode tab. Reverse leakage is 5 µA at 400 V, and the junction temperature rating extends to 175 °C max. The 175 °C Tj ceiling gives margin in a hot enclosure — the diode's forward voltage drop increases with temperature, so the actual conduction loss at 125 °C ambient is higher than the 25 °C datasheet figure; derate the average current if the board sees sustained airflow above 85 °C.