1 kV fast recovery in a DO-201AD axial package
The STTH310RL is a 1000 V, 3 A fast recovery rectifier from STMicroelectronics. Its 75 ns trr puts it in the fast-recovery class at 1 kV blocking voltage. The DO-201AD axial package is a through-hole format — the cathode band and lead diameter match the standard axial diode hole pattern for wave-solder assembly.
At 3 A forward current and 1000 V reverse, the 75 ns trr sets the crossover loss in a hard-switched converter. Forward voltage is 1.7 V max at 3 A, which is higher than a standard 1 kV rectifier (typically 1.1 V) but the trade-off is the recovery speed. For a continuous 3 A load the conduction loss is 5.1 W; the junction-to-ambient thermal resistance of the DO-201AD in still air is about 50 °C/W, so a 175 °C junction rating gives enough headroom for a 70 °C ambient without a clip-on heatsink.
Junction temperature and the 175 °C ceiling
Reverse leakage at 1000 V is 10 µA at 25 °C, but it doubles every 10 °C above that — at 125 °C junction the leakage is roughly 160 µA, which adds 0.16 W of standing loss that the thermal model must include.