1500 W pulse rating and clamping decision
The 1.5SMC120CA-M3/9AT: That 1500 W rating sets the energy-handling ceiling — a transient that stays within the 165 V clamping limit at 9.1 A peak pulse current will be shunted without damage to the TVS or the downstream circuit. The breakdown range starts at 114 V, so the TVS stays off during normal operation and only conducts when the line exceeds that threshold.
Housed in a DO-214AB (SMC) package, the 1.5SMC120CA-M3/9AT is a surface-mount device with a standard JEDEC footprint. The SMC body is larger than the SMA/SMB siblings — it handles the 1500 W pulse without exceeding the junction temperature limit of 150°C. Operating temperature spans -65°C to 150°C, so it suits outdoor enclosures and unheated industrial cabinets where ambient extremes are common.