600W bidirectional TVS in a DO-214AA (SMB) package
It is rated for 600W peak pulse power (10/1000µs waveform) and can handle a peak pulse current of 147A under an 8/20µs pulse shape. The device clamps at a maximum of 27.2V at its rated current, protecting downstream circuitry from voltage spikes. Its 12.8V reverse standoff voltage makes it suitable for protecting 12V nominal rails or signal lines.
The SM6T15CA has a minimum breakdown voltage of 14.3V and a maximum clamping voltage of 27.2V at the peak pulse current. For a 12V rail, this provides a comfortable margin: the TVS stays off under normal conditions but triggers well before the voltage reaches levels that would damage typical 12V-rated ICs or modules. The 27.2V clamp is the hard ceiling the protected node sees during a surge event. This figure must be below the absolute maximum rating of every component on that net — if a downstream part is only rated to 25V, this TVS will not protect it; a lower-voltage clamp (e.g., from the SM6T family with a lower standoff) would be needed.