The STPS30SM80CG-TR is a dual Schottky rectifier in a common-cathode configuration, each diode rated for 15 A average at 80 V reverse. The D2PAK surface-mount package with exposed tab handles the thermal load — the tab is the cathode common, so the board copper plane does double duty as heat sink and current path. Forward voltage is 790 mV maximum at 15 A; reverse leakage is 40 µA at 80 V. The junction temperature ceiling is 175°C, which gives headroom in a hot PSU or OR-ing diode application.
Pin-compatible alternatives — what to look for
For a pin-compatible replacement, look for a dual common-cathode Schottky in D2PAK rated at least 80 V and 15 A per diode, with a forward voltage at or below 790 mV at 15 A. The tab is the common cathode — any substitute must match that pinout to avoid a board spin.