What the clamping specs mean for the board
The 1.5SMCJ64CA-AQ: The 64 V reverse standoff rating is the working voltage the TVS diode presents to the line — the circuit runs at or below this without the device conducting.
Automotive temperature grade and package
The DO-214AB (SMC) package is the standard pick-and-place surface-mount outline for this power class; the 1.5 kW dissipation in this footprint demands a thermally adequate landing pad on the PCB to stay within the junction limit.
