Clamp threshold for a 150 V rail
Its reverse standoff voltage is 150 V, and the minimum breakdown voltage is 167 V — so the part stays transparent below 150 V and starts clamping above 167 V. With a single bidirectional channel, this device handles surges of either polarity on the same line — useful for AC-coupled signals or bipolar DC buses where a unidirectional part would need an external bridge.
Surge energy and thermal margin
The peak pulse current at that waveform is 1.9 A. For a 150 V rail, the 500 W rating means the device can absorb a 268 V clamp at 1.9 A before the junction exceeds 150°C. Derate linearly above 25°C ambient; the DO-214AC (SMA) package has a typical junction-to-ambient thermal resistance around 90°C/W, so a 1.9 A pulse at 25°C ambient leaves about 80°C margin to the 150°C limit.