The STMicroelectronics SM6T30AY is a unidirectional Zener-type transient voltage suppressor (TVS) diode rated for 600W peak pulse power (10/1000µs waveform) and qualified to AEC-Q101. It is designed to protect a 24V nominal automotive DC bus or load-dump-sensitive circuit: the 25.6V reverse standoff voltage (Vrwm) is the maximum DC voltage the device can hold without conducting, while the 28.5V minimum breakdown voltage (Vbr) defines the threshold where clamping begins. At the full rated peak pulse current of 75A (8/20µs), the voltage is clamped to a maximum of 53.5V — the level a downstream ECU or sensor module must survive. The single unidirectional channel is polarity-specific, so the cathode band or package marking must align with the protected rail.
AEC-Q101 — the qualification that opens the BOM
For a Tier 1 or OEM program, that qualification is the gate: an industrial-grade TVS with the same electrical ratings cannot be substituted without a waiver or re-qualification. The supplier device package is SMB (DO-214AA), a standard surface-mount footprint shared by other 600W TVS diodes in the SM6T family.
Package and footprint — SMB (DO-214AA)
The SM6T30AY is supplied in a DO-214AA (SMB) package for surface-mount assembly. The package is rated for the full junction temperature range and the 600W pulse without derating at 25°C ambient — check the thermal curve in the datasheet for elevated-temperature derating.