What this Schottky pair brings to the rail
Its key efficiency number is 550 mV forward voltage drop at 10 A per diode — that is the number that determines how much heat you have to pull out of the TO-220FP full-pack case. This is a standard-recovery Schottky (recovery < 500 ns), so it is suited for 50/60 Hz line-frequency rectification and low-frequency DC-DC converters where switching speed is not the limiting factor.
Forward voltage — the number that drives the heatsink
At 10 A per diode the forward drop is 550 mV max. That is a typical Schottky figure for a 45 V part at this current level. In a 20 A total load, each diode carries 10 A, so the conduction loss per diode is about 5.5 W — total 11 W if both diodes conduct continuously. The TO-220FP case has higher thermal resistance than a standard TO-220 because the plastic isolates the tab, so you need to account for that in the heatsink calculation.
Package and mounting — field-swap friendly
Through-hole TO-220FP, three leads, common-cathode configuration. The full-pack case has no exposed metal tab, so no insulating washer is needed when mounting to a chassis or heatsink. That is a real advantage for a field swap: you can pull the old part, drop this one in, and torque it down without hunting for a mica insulator or thermal pad. Orientation is obvious — the tab is the cathode common, and the two anode pins are symmetric.
Lifecycle — still a current-production line item
STMicroelectronics lists the STPS20L45CFP as an active product. The base product number STPS20 covers a family of 45 V and 60 V variants in different packages; the CFP suffix specifically identifies the TO-220FP full-pack version.