The 100 V reverse voltage rating gives headroom for 48 V bus rails and 72 V automotive transient peaks. Junction temperature is rated to 175°C, so it can live in an under-hood or industrial enclosure without derating panic. The Q Automotive series designation means this part was originally qualified for automotive applications, though with the obsolete status, new-vehicle production designs should look at current-generation alternatives.
Obsolete — sourcing the STPS80H100CY today
STMicroelectronics lists the STPS80H100CY as obsolete. No lead-time number from the factory exists because the factory no longer makes it. If you are qualifying a replacement, look for a common-cathode Schottky in TO-247-3 rated at 100 V and 40 A per diode with a junction temperature of at least 175°C. The STPS80H100CY has no official successor listed by ST, so the cross-reference search falls to parametric matching.
Field-swap friendly — TO-247-3 with through-hole leads
The TO-247-3 package is a through-hole part with three leads and a large tab for heatsinking. No hot-air station, no reflow profile — just a soldering iron and a screw hole for the heatsink. Orientation is obvious: the common-cathode pair has the two anodes on the outer pins and the shared cathode on the center pin (pin 2). Marking is clear on the body.