30 ns reverse recovery — the switching-loss floor
The STTH1R02QRL is a 200 V, 1.5 A fast-recovery rectifier from STMicroelectronics, built with standard planar technology and specified for a 30 ns reverse recovery time.
1.5 A average, 1 V forward — the thermal budget
At 1.5 A forward current the maximum forward voltage is 1 V, which puts the conduction loss at 1.5 W steady-state. In a DO-15 axial package with the leads soldered into a PCB and no added heatsink, that 1.5 W raises the junction temperature by roughly 50–60 °C above ambient — the 175 °C maximum junction rating leaves enough headroom for a 105 °C ambient in a power supply or motor-drive auxiliary rail.