Bidirectional TVS for 24V and 48V vehicle bus protection
The STMicroelectronics SM30T47CAY is a bidirectional Zener transient voltage suppressor from the AEC-Q101 qualified TRANSIL™ SM30TY series, designed to clamp voltage transients on automotive power and signal lines. It delivers a peak pulse power of 3000W (10/1000µs waveform) with a reverse standoff voltage of 40V, making it suited for protecting 24V and 48V nominal rails from load-dump and inductive-switching surges.
Voltage clamping window and surge capability
The SM30T47CAY holds a minimum breakdown voltage of 44.4V and a maximum clamping voltage of 64.5V at the rated peak pulse current of 43.5A. That clamping ceiling keeps the protected rail below the typical 65V to 70V absolute maximum of downstream DC-DC converters and linear regulators used in automotive ECUs.
Package, footprint, and mounting
The device comes in a standard SMC surface-mount package. The SMC footprint is shared across many 3000W TVS parts, so the board layout can accommodate alternate sourcing without a respin. No power line protection is integrated — this is a standalone transient clamp, not a filtered or protected port.