The STTH15L06FP is a 600 V, 15 A fast-recovery epitaxial diode from STMicroelectronics, built for continuous-current PFC boost stages and hard-switched flyback converters where reverse recovery time directly sets the switching loss and the snubber bill of materials. Its 85 ns reverse recovery time (trr) at rated current means the diode exits conduction fast enough to keep the MOSFET turn-on overlap short — you can push the switching frequency past 100 kHz without cooking the junction or adding a lossy snubber across every cycle.
600 V blocking, 15 A average — sizing the part
Rated for 600 V DC reverse (Vr) and 15 A average rectified current (Io), this diode fits 400 V bus PFC stages with healthy derating and can handle the repetitive peak currents in a 1–2 kW power supply output rectifier. Maximum forward voltage is 1.55 V at 15 A and 175°C junction temperature — the conduction loss at full load runs about 23 W, so the TO-220FPAC isolated tab needs a heatsink sized for that dissipation, but the isolated tab saves you the cost and assembly step of a separate insulating pad.