Dual 20 A Schottky for the 150 V rail — what the ratings mean
The STPS40150CGY-TR is a dual Schottky rectifier from STMicroelectronics, configured as a common-cathode pair in a single D²PAK (TO-263) package. Each diode is rated for 20 A average rectified current at a 150 V DC reverse voltage, with a maximum forward voltage of 920 mV at that 20 A current. This places it in the 150 V / 20 A per-channel power rectification tier — the part you reach for when you need a low-Vf Schottky on a 12 V or 24 V automotive bus with headroom for load-dump transients, or in a 48 V telecom rectifier stage where the 150 V Vr gives margin above the nominal rail.
175 °C junction and AEC-Q101 — the automotive-grade reality
This part is specced for under-hood automotive environments, engine-bay electronics, and any high-ambient industrial application where a 150 °C junction ceiling would leave no margin. The ECOPACK2 RoHS compliance is standard for this tier, but the AEC-Q101 trace is what a Tier-1 buyer's quality team will check first.
D²PAK footprint — thermal design for 40 A total
The D²PAK (TO-263-3) package with exposed tab is the standard surface-mount format for dissipating 40 A total (20 A per diode). The tab is the thermal path — board layout needs a sufficient copper area and a via stitch to the inner ground plane to keep the junction below 175 °C at full load. The 920 mV forward drop at 20 A means about 18.4 W per diode at peak current; the thermal pad and board copper are what carry that heat, not the package itself.
For the BOM buyer, this means the part can be committed to a production build without an obsolescence risk horizon.