80 V, 15 A Schottky pair in a TO-220-3
The STPS30SM80CT is a dual Schottky rectifier from STMicroelectronics, configured as a common-cathode pair in a single TO-220-3 through-hole package. Reverse leakage is 40 µA at the 80 V rated reverse voltage. The junction temperature rating goes to 175°C, which gives thermal headroom in high-ambient environments like power supplies and motor drives, but the TO-220 tab must be heatsunk to keep the die below that ceiling under load.
STMicroelectronics lists the STPS30SM80CT as Obsolete. The common-cathode configuration is the topology constraint — any replacement must share that pinout.
Conduction loss and thermal budgeting
At 15 A per diode, the 790 mV forward drop gives about 11.85 W conduction loss per die. In a common-cathode pair carrying 30 A total, that is nearly 24 W of heat to pull through the TO-220 tab into a heatsink. The 175°C junction ceiling is the absolute limit — derate for ambient temperature and mounting interface. The 40 µA leakage at 80 V reverse is a standby-loss contributor at high temperature.