TVS clamping ratings and what they mean for the protection circuit
The 1.5SMC8.2CAHM6G: The clamping voltage of 12.1 V at 130 A peak pulse (10/1000 µs) tells you the maximum voltage the protected node sees when the surge hits — this, not the standoff or breakdown figure, is what you compare against your downstream IC abs-max rating. The 7.02 V reverse standoff sits below the 7.79 V minimum breakdown — the device stays dormant on the line at normal operating voltage and activates only when a transient pushes the rail above breakdown.
SMC package and the layout consequence
The DO-214AB (SMC) is the mid-size TVS package — the cathode bar is the thermal interface, so the copper pad area under the device and the via array to the ground plane determine how effectively heat leaves the junction during a surge event. Tape-and-reel packaging suits high-volume pick-and-place lines; the 1.5 kW peak pulse rating requires the PCB designer to verify thermal pad solder joint integrity under repetitive thermal stress if the application sees frequent transients.