The STTH110A is a 1000 V, 1 A fast-recovery rectifier from STMicroelectronics, with a 75 ns reverse recovery time that puts it in the ultrafast class. It is built for continuous-current-mode PFC boost stages, flyback snubbers, and output rectification in 400 V bus power supplies where switching losses matter. The 1.7 V forward drop at 1 A is typical for a 1 kV device — the trade-off for the high voltage blocking and fast turn-off.
A 75 ns reverse recovery time at 1 A and 1000 V means the diode can switch at 100 kHz or higher without excessive reverse-recovery losses. In a PFC boost stage running a 400 V DC bus, that trr keeps the MOSFET turn-on current spike low enough to avoid ringing and EMI filter headaches. It is also fast enough for the secondary-side rectification in a 100 W to 300 W flyback converter, where the diode's recovery charge directly affects the leakage-inductance reset time.
DO-214AC SMA — rework and footprint notes
The SMA package is a JEDEC standard outline, so the footprint is shared with dozens of other 1 A rectifiers from various vendors. It is a two-pin surface-mount part with a clear cathode band — pin 1 orientation is unambiguous under a hot-air station. The plastic body is MSL 1 per the package family, so no bake required before reflow as long as the reel seal is intact. For hand rework, a 350 °C hot-air nozzle at low flow lifts the part cleanly without lifting the pad, provided the board has a thermal relief on the cathode pad.