STMicroelectronics lists the STPS20M100SR as Obsolete. No stock-holding claim is made here.
Rated 20 A average rectified current (Io) with a 100 V maximum DC reverse voltage (Vr). Reverse leakage is 40 µA at the 100 V rated reverse voltage — this leakage doubles with temperature, so at elevated junction temperatures the standing loss in a blocking state becomes a non-trivial contributor to the thermal budget.
TO-262 I2PAK — rework and board-fit
Through-hole TO-262-3 Long Leads (I²Pak, TO-262AA) package. The three leads are formed for through-hole insertion; the tab is the cathode and the primary heat path. The long-lead variant gives extra stand-off from the board, useful when the tab is bolted to a heatsink that sits above the PCB plane.
Fast-recovery Schottky — speed class
Listed as Fast Recovery =< 500 ns, > 200 mA (Io). This is a Schottky barrier diode — the recovery mechanism is majority-carrier, so the reverse-recovery charge is negligible compared to a pn-junction fast-recovery diode. The 500 ns upper bound is a classification marker, not a switching-speed limit; the actual reverse-recovery time is in the tens of nanoseconds.