Clamping and peak-pulse ratings
The 1.5SMCJ64A-AQ: 64 V reverse standoff is the working rail — the TVS sits idle below this and clamps only when a transient spikes above the 71.1 V breakdown minimum. When it fires, the 103 V clamping maximum at 14.6 A peak pulse (10/1000 µs) keeps the protected node below 103 V; that ceiling is what the downstream silicon must survive. 1500 W peak pulse rating defines the surge energy the device absorbs on a single 10/1000 µs event — the 14.6 A rating is the current the clamping voltage is specified at, not a limit for continuous conduction.
Automotive grade in DO-214AB SMC
SMC (DO-214AB) is the mid-size automotive TVS footprint — the rectangular body and solder-wing termination are pick-and-place compatible and reflow-soldered to the PCB; the cathode band marks the anode on the unidirectional orientation, so board polarity matters.