Automotive-grade 1.5 kW TVS for 12 V bus protection
The STMicroelectronics SM15T18AY is a 1500W unidirectional TVS diode from the AEC-Q101-qualified SM15TY TRANSIL™ series, designed for surge protection on automotive power and signal lines. With a 15.3 V reverse standoff voltage and a 32.5 V clamping point, it sits directly on 12 V battery rails, load-dump clamps, and ISO 7637-2 pulse suppressors.
Clamping window and surge rating
The 17.1 V minimum breakdown voltage gives a clean trigger point above the 15.3 V standoff, while the 32.5 V clamp keeps the protected rail inside the typical 36 V absolute-max of downstream ECUs and sensors. Peak pulse current is rated at 308 A for an 8/20 µs waveform — enough to handle the ISO 7637-2 pulse 5a load-dump energy in a 12 V system.