1000 V, 30 A, 100 ns — the PFC and SMPS output diode
The STTH3010W is a 1000 V, 30 A fast recovery diode from STMicroelectronics in a DO-247 through-hole package.
At 30 A and 1000 V blocking, a 100 ns trr keeps the reverse recovery charge low enough that a 50-100 kHz hard-switching converter stays within junction temperature. The 175 °C max Tj rating gives headroom for the heatsink design — you are not forced into a larger package or a SiC diode unless the frequency pushes past 150 kHz. Forward voltage is 2 V max at 30 A. That is 60 W conduction loss at full load, which lands on the heatsink. The DO-247 tab is the thermal path — bolt it to a finned heatsink with thermal compound and the junction-to-case thermal resistance stays under control.