600 V, 1 A, 80 ns — the rectifier for PFC and flyback snubbers
The STTH1L06 is a 600 V, 1 A general-purpose fast recovery diode in the through-hole DO-41 (DO-204AL) package. The 1.3 V maximum forward voltage at 1 A (Vf) is a conduction-loss figure that matters at the high end of the current rating — at 0.5 A the Vf drops, so the average dissipation in a typical 50 W flyback output is under 0.5 W, well within the DO-41's thermal budget when the leads are soldered into a 1.6 mm board.
175 °C junction — margin for the hot spot
Rated for a maximum junction temperature of 175 °C, the STTH1L06 leaves headroom above the 150 °C typical of many standard-recovery diodes. In a cramped power supply where the ambient around the diode reaches 85 °C and the self-heating adds another 40 °C, the junction stays below the 150 °C derating line — no need to oversize to a higher-current part just for thermal margin. Reverse leakage is specified at 1 µA at the full 600 V reverse voltage (Vr). That figure is at 25 °C; leakage doubles roughly every 10 °C, so at 125 °C junction it will be in the tens of microamps — still negligible for the bias network in a PFC controller's auxiliary winding.
Active production, ROHS3 — no lifecycle risk for a new BOM line
The base product number STTH1 covers a family of fast-recovery diodes at different voltage and current ratings sharing the same DO-41 footprint. The STTH1L06RL variant (Tape & Reel packaging) is the same die — the BOM can switch between the two without requalifying the electrical performance.