Fast recovery rectifier for PFC and SMPS output stages
The STTH3L06U is a 600 V, 3 A fast recovery rectifier from STMicroelectronics in an SMB surface-mount package. Its 85 ns reverse recovery time (trr) places it in the fast-recovery class — built for continuous-conduction-mode (CCM) boost PFC stages and high-frequency output rectification in switched-mode power supplies, where a standard recovery diode would burn through the switching loss budget.
The 85 ns trr at rated conditions means the diode recovers before the MOSFET in a boost PFC turns back on, minimising the reverse-recovery current spike that otherwise adds EMI and shoot-through stress. Forward voltage is 1.3 V maximum at 3 A — at full rated current the diode dissipates about 3.9 W. In an SMB package that means the PCB must pull heat through the solder joint and into a copper pour; a 1 oz copper pad of at least 300 mm² keeps the junction below 125 °C in still air.