1200 V blocking in an SMA — the standout spec
The STTH112A is a 1200 V, 1 A ultrafast diode from STMicroelectronics in a DO-214AC (SMA) package. The 1200 V reverse voltage rating is the headline — it lets you use a single diode in 400 VAC PFC stages or 800 VDC bus rails without stacking series devices.
75 ns trr — recovery speed for the switching loop
The 75 ns trr places this diode in the ultrafast class, suitable for continuous-conduction-mode PFC and output rectification in 100–200 W offline supplies. The 1.9 V forward drop at 1 A is the conduction-loss trade-off for the high voltage rating — expect the junction to run hotter than a 600 V ultrafast at the same current.