90 ns reverse recovery at 1 kV — the switching edge
The STTH1210D is a 1 kV, 12 A fast recovery diode from STMicroelectronics with a reverse recovery time (trr) of 90 ns. This combination of high blocking voltage and fast turn-off places it in the boost-PFC stage of switch-mode power supplies and in flyback converters where the diode must snap off cleanly before the next switching cycle begins.
Forward voltage and leakage — the thermal budget
Maximum forward voltage is 2 V at 12 A, which sets the conduction loss floor. Reverse leakage at rated blocking voltage is 10 µA — negligible at room temperature but it rises exponentially with junction temperature. The maximum junction temperature is 175 °C, so the designer must account for the Vf × If product plus the leakage power at high line in the heatsink calculation.