AEC-Q101 qualified TVS for automotive power bus protection
The Vishay 1.5KE9.1CAHE3_A/C is a 1500W bidirectional TransZorb TVS diode in the AEC-Q101 automotive series — the same TransZorb family used in engine control and transmission modules where a single surge event can write off a ECU if the clamp doesn't hold. Rated for a 7.78V reverse standoff with an 8.65V minimum breakdown and 13.4V clamping at 112A peak pulse current (10/1000µs waveform), this part sits on a 12V nominal automotive rail — the 7.78V standoff clears the battery voltage during cranking, while the 13.4V clamp catches load-dump transients before they reach the downstream regulator.
An engine-bay ECU that sees 125°C ambient on a hot day still has 50°C margin before the junction limit, but the derating curve for peak pulse power above 25°C must be applied per the TransZorb application note. Through-hole DO-201AA (DO-27) axial package — the leads carry the surge current into the PCB copper pour. The 1500W rating assumes a 25°C ambient with the leads soldered to a minimum 30mm² copper pad on each side; a smaller pad area or a lifted lead reduces the surge capability.
Sourcing posture for this automotive TVS
The AEC-Q101 qualification means PPAP documentation is available from the manufacturer — an OEM auditor will accept the AEC-Q101 report in lieu of a separate PPAP submission for this part.