120 V, 20 A Schottky in a TO-220AC — what it handles
The STPS20120D is a 120 V, 20 A Schottky rectifier from STMicroelectronics in a through-hole TO-220AC package. It's built for the output stage of switch-mode power supplies, freewheeling diodes in motor drives, and polarity protection in battery-fed circuits — anywhere you need low forward drop and fast switching with a 175°C max junction temperature.
At 20 A the forward drop is 930 mV — that's the conduction loss floor at full load. The 20 µA reverse leakage at 120 V is typical for a 120 V Schottky; it rises with temperature, so the thermal budget at high Tj is dominated by leakage, not forward drop. The 175°C junction rating gives headroom for aggressive heatsink sizing in confined enclosures.
ST lists the STPS20120D as Active. ROHS3 compliant.