Transient protection for a 12.8 V rail
The STMicroelectronics SM15T15A is a unidirectional TRANSIL™ TVS diode designed to clamp voltage transients on a nominal 12.8 V DC rail. It provides a single channel of protection with a peak pulse power rating of 1500W (1.5kW) under the 10/1000 µs waveform, making it suitable for general-purpose surge suppression in industrial, telecom, and automotive auxiliary circuits.
Clamping voltage and breakdown threshold
The reverse standoff voltage is 12.8 V, meaning the diode presents high impedance below this level and does not load the protected rail. Breakdown occurs at a minimum of 14.3 V, which is the threshold where the device begins to conduct. Under a peak pulse current of 368 A (8/20 µs waveform), the clamping voltage is held to a maximum of 27.2 V. This clamping ceiling determines the voltage stress the downstream circuitry must survive during a transient event.
Package and mounting
The SM15T15A uses the SMC package, a common footprint for medium-power TVS diodes. It is surface-mount only, with the cathode band marking the unidirectional orientation.
Lifecycle and sourcing
For BOM planning, the active status removes near-term obsolescence risk, though lead times and minimum order quantities still apply.