The 1.5SMCJ75CA_R1_00001: The 75 V reverse standoff (typ) is the working voltage the line sits at during normal operation — the TVS stays off and draws only leakage current until a surge exceeds this threshold. When the transient arrives, breakdown kicks in at 83.3 V minimum — that is the guaranteed onset voltage at the specified test current. The bidirectional configuration means a single device clamps both polarities — no need to stack two unidirectional parts for AC or reversible DC rails.
Junction temperature and thermal margin
The DO-214AB SMC package in a properly thermally loaded board layout carries the transient heat away during the pulse; the peak-pulse power spec (1.5 kW) is defined on the 10/1000 µs waveform, not a continuous rating — sustained or repetitive transients need separate thermal analysis.