50 ns reverse recovery — what it buys the PFC stage
The STTH8R03DJF-TR is a 300 V, 8 A fast-recovery epitaxial diode from STMicroelectronics, built for continuous-current-mode (CCM) power-factor-correction boost stages and high-frequency output rectification in switch-mode supplies. Its 50 ns reverse recovery time (trr) keeps switching losses low at frequencies where a standard recovery part would overheat the junction. The 1.3 V forward drop at the full 8 A rated current is a straight conduction-loss number for the thermal budget — at 8 A average that's about 10.4 W of forward dissipation, so the PowerFlat 5x6 exposed pad needs a solid via-stitched copper pour to keep Tj under the 175°C maximum.
Package and thermal — PowerFlat 5x6 layout notes
This diode comes in an 8-PowerVDFN package, ST's PowerFlat 5x6 footprint. The part is surface-mount only, so reflow profile follows standard Pb-free solder reflow for the PowerFlat package.