The STPS40L15CW is a dual common-cathode Schottky rectifier in a TO-247-3 through-hole package. The forward voltage drop is 410 mV at 19 A — low enough to keep conduction losses manageable in a 40 A total output stage. Reverse leakage is 6 mA at the rated 15 V, which is typical for a low-Vf Schottky at this current level and matters if the design idles with the diode reverse-biased at high junction temperature. The recovery speed is listed as fast recovery ≤ 500 ns at > 200 mA, which is standard for a power Schottky — the Schottky barrier itself has no stored charge, so the speed is limited by the package and test circuit parasitics. The 125°C maximum junction temperature is the thermal ceiling; any replacement candidate must match or exceed that for the same heatsinking conditions.
Where this part was used and what to look for in a substitute
A dual 20 A common-cathode Schottky in TO-247-3 is typically found in output rectification for low-voltage, high-current switchmode supplies — think 5 V or 3.3 V rails in telecom rectifiers, server PSUs, or battery charger output stages. The 15 V reverse rating limits it to sub-12 V output rails with adequate derating. The common-cathode configuration is convenient for center-tapped secondary windings or as a pair of OR-ing diodes sharing a heatsink.
Package and mounting — through-hole only
The STPS40L15CW comes in a TO-247-3 through-hole package only. There is no surface-mount variant of this specific part number. The TO-247-3 has a large metal tab for heatsink mounting — plan for a screw or clip attachment and thermal interface material. The through-hole leads are sized for soldering into plated through-holes on a PCB or for wiring to a terminal block in a chassis-mount assembly.