1500 W peak pulse in a DO-214AB footprint
The 1.5SMC18AHM3_A/H is a 1500 W peak-pulse Zener TVS diode from Vishay's automotive-grade 1.5SMC TransZorb series, qualified to AEC-Q101 for use in under-hood and chassis electronics where transient suppression must hold within tolerance over the full -65 °C to 150 °C junction temperature range. Housed in the DO-214AB (SMC) surface-mount package, it clamps a 15.3 V reverse standoff rail to 25.2 V maximum at a peak pulse current of 59.5 A (10/1000 µs waveform), which means a 12 V automotive bus sees the clamp voltage stay below the 30 V abs-max of downstream ECUs during a load-dump or inductive kickback event.
Clamping voltage and breakdown margin
Minimum breakdown voltage is 17.1 V, giving a 1.8 V guard band above the 15.3 V standoff — this margin ensures the diode does not conduct during normal 12 V system ripple (up to 16 V typical) but fires before the protected IC's abs-max rating is reached. The unidirectional single-channel design (one channel) is intended for DC rails where reverse polarity is handled separately; for AC or bidirectional lines, a bidirectional variant from the same 1.5SMC family would be the correct fit.
Automotive qualification and sourcing posture
No pin-compatible second-source is listed on the official record, so the Vishay part number is the sole qualified option for this specific clamp voltage and package.