AEC-Q101 qualification and temperature envelope
The 1.5SMC30CAHM3_A/I: Its junction temperature range of -65°C to 150°C covers the full automotive ambient without derating — a 125°C engine-bay soak leaves 25°C margin to the absolute max junction. The clamping voltage at that peak current is 41.4V max when the surge current reaches 36.2A — this is the voltage the protected electronics actually sees during the transient, so the downstream component's breakdown rating must exceed this clamp level.
Standoff and breakdown — the BOM-fit parameters
The reverse standoff voltage is 25.6V, which is the maximum DC or peak AC voltage the TVS can block without conducting in steady state — a 24V automotive bus with 25.6V absolute max rail sits right at this limit. It eliminates the need for two back-to-back unidirectional TVS diodes, saving board area and BOM line count.
Package and board-fit for the DO-214AB
The copper area under the tab on the PCB sets the junction-to-ambient thermal resistance — for the 1500W pulse rating, a minimum 645mm² copper pad per the Vishay application note is typical to keep the junction rise within limits during repetitive surge events.