TVS for 12V automotive rails
The 1.5SMC15CAHM3/I: It clamps transients on 12 V nominal rails — the 12.8 V reverse standoff voltage sits just above the battery's steady-state ceiling, so it stays out of conduction during normal operation and only fires when a load-dump or inductive kick pushes the bus above 14.3 V breakdown.
Pulse handling and clamping
The 21.2 V clamp is the maximum voltage the protected circuit sees — a 12 V ECU rail with 40 V tolerant downstream parts has plenty of margin even at the clamp ceiling.
Automotive temperature and package
Operating junction temperature spans -65 °C to 150 °C, covering under-hood and cabin environments.