45 ns reverse recovery — the switching-loss ceiling
The STTH1R06AF is a 600 V, 1 A fast-recovery diode from STMicroelectronics, specified with a 45 ns reverse recovery time. That 45 ns trr is the number that decides whether this part works in a hard-switched PFC boost stage at 100 kHz or gets swapped for an ultrafast sibling. At 1 A forward current and 600 V blocking, it sits in the sweet spot for 100–200 W power supplies, LED drivers, and flyback clamp circuits.
Forward drop and leakage at temperature
Forward voltage is 1.9 V maximum at 1 A — a typical figure for a 600 V fast-recovery diode in this current class. Reverse leakage is 1 µA at 600 V, but that figure rises with junction temperature; the 175°C maximum junction rating gives headroom for high-ambient PFC layouts where the diode shares a heatsink with the MOSFET.
SOD-128Flat — low-profile, automated assembly
The SOD-128Flat package (ST's own SOD128Flat supplier device code) is a surface-mount, flat-lead design with a low profile suitable for dense PFC boards. It is supplied on Tape & Reel, which feeds pick-and-place without a tube changeover. The flat leads improve solder-joint inspection access compared to a gull-wing, and the package footprint is compact enough for 1 A continuous without a large copper island.
ROHS3 compliant per the listing.