The STPS745G-TR is a 45 V, 7.5 A Schottky rectifier from STMicroelectronics in a D²PAK (TO-263AB) surface-mount package. The 7.5 A average rectified current (Io) is the continuous forward rating at case temperature — the actual current you can pull depends on the copper pad area under the tab and the airflow across the board. The 45 V reverse voltage ceiling gives you headroom on a 24 V bus (1.9× margin) but is tight for a 48 V rail where you want 60 V or 100 V parts.
Forward drop and thermal budget
The forward voltage is specified at 840 mV maximum at 15 A — that is twice the rated average current, so it captures the inrush or surge condition. At the 7.5 A continuous point the Vf will be lower, but the 840 mV figure at 15 A is the number to use for worst-case conduction loss in a hot environment. The junction is rated to 175°C maximum, which is the Schottky-class ceiling — useful for power supplies in enclosed industrial boxes or under-hood automotive where ambient air is 85°C or higher.
Reverse leakage at temperature
Reverse leakage is 100 µA at 45 V and 25°C junction. Like all Schottky diodes, leakage rises exponentially with temperature — at 125°C junction the leakage can be 10× to 20× higher. That leakage current adds to the thermal budget and can become the dominant loss mechanism in a lightly loaded OR-ing or reverse-polarity protection circuit. If the application runs the diode hot and the load is only a few milliamps, the leakage current may exceed the load current and the diode never fully blocks.
The tab is the cathode connection and the primary thermal path. The datasheet thermal resistance assumes a minimum copper pad area on the PCB — typically 1 square inch of 2-oz copper on the top layer with vias to an inner plane. Without that copper area the junction temperature rises above the 175°C limit at 7.5 A continuous.
It is ROHS3 compliant.