Dual Schottky rectifier for 120 V rails — what the ratings mean
The fast recovery characteristic (≤500 ns, >200 mA) is typical for a Schottky barrier; the switching losses are low enough for 50–100 kHz SMPS designs without a snubber.
Procurement for the STPS40SM120CT goes through the surplus and broker channel.
Common-cathode pair — board-level fit
The two diodes share a common cathode (pin 2 and tab), with the anodes on pins 1 and 3 — the standard pinout for a TO-220 dual rectifier used in center-tap full-wave rectifiers or OR-ing configurations. Reverse leakage at 120 V is 275 µA — this rises with junction temperature and should be factored into the standby loss budget for a 120 V rail.