Clamping voltage and breakdown margin
The 1.5SMC300CA: That margin absorbs transients without the rail itself exceeding the downstream components' abs-max rating. The bidirectional configuration (single channel) means it clamps both positive and negative transients symmetrically, so orientation on the PCB is non-critical — useful for AC-coupled signal lines or floating supplies.
Package and temperature range
The SMC footprint is standard for 1.5kW TVS diodes; the wide temperature range covers industrial and telecom enclosure environments without derating at the high end.
Active production and sourcing
It is a standard catalog TVS diode in the 1.5SMC family, with no announced end-of-life or last-time-buy.