The STMicroelectronics SM15T27CAY is a bidirectional Zener TVS diode from the SM15TY TRANSIL™ series, qualified to AEC-Q101 for automotive applications. It is designed to clamp transients on a nominal 24 V DC bus, with a reverse standoff voltage of 23.1 V and a minimum breakdown voltage of 25.7 V. The 1500 W peak pulse power rating (10/1000 µs waveform) means it can absorb substantial surge energy from load dump or inductive kickback events common in automotive power distribution. The clamping voltage is held to 48.3 V maximum at the peak pulse current of 207 A (8/20 µs waveform), which keeps the protected downstream circuitry within a safe voltage ceiling.
AEC-Q101 qualification and automotive deployment
This qualification is mandatory for Tier-1 suppliers placing TVS diodes in ECUs, transmission controllers, or any module that must survive the automotive reliability validation flow.
Package and footprint — DO-214AB SMC
The SM15T27CAY is supplied in the SMC package, a surface-mount footprint rated for the 1500 W pulse dissipation. The SMC body is larger than the smaller SMA/SMB packages, which helps spread the thermal pulse into the PCB copper. The part is bidirectional in a single package, so no polarity orientation is needed on the board — it clamps equally on positive and negative transients. The mounting is surface-mount only, compatible with standard reflow soldering profiles.