800 V 2 A fast recovery — 75 ns trr
The STTH208 is a 800 V, 2 A general-purpose fast recovery diode from STMicroelectronics, in a through-hole DO-15 axial package. Its 75 ns reverse recovery time suits it for continuous-conduction-mode PFC boost stages, flyback snubbers, and secondary-side freewheeling in 400 V bus designs where switching loss matters.
75 ns trr — switching loss and snubber design
At 75 ns trr the STTH208 recovers fast enough to keep reverse-recovery charge low in a 100 kHz PFC stage, reducing the MOSFET turn-on loss and snubber power dissipation. The 1.65 V forward drop at 2 A is a typical ultrafast-recovery trade-off — the faster the recovery, the higher the Vf.
Rated for 175°C maximum junction temperature — this gives headroom in a cramped power supply where ambient around the diode may reach 85°C. The DO-15 axial package relies on the lead length and PCB copper for heat sinking; a 2 A average current at high ambient will need adequate trace width to keep Tj below the ceiling.
Reverse leakage at rated voltage
Maximum reverse leakage is 5 µA at 800 V — a low figure that minimises standby loss in offline supplies. Leakage doubles roughly every 10°C above 25°C, so at 125°C Tj it may reach 40–80 µA, still acceptable for most flyback and PFC applications.