Automotive-grade transient protection for 128V rails
The 1.5SMC150CAHM3/H: The 128V reverse standoff voltage means the protected rail can carry up to that level continuously without the diode conducting leakage. Breakdown starts at 143V minimum, giving a 15V margin before clamping engages — typical for 120V nominal automotive or telecom buses that see transients well above the DC level.
DO-214AB SMC footprint and thermal path
Housed in the standard DO-214AB (SMC) surface-mount package, the same footprint used across the 1.5SMC family. The large copper tab on the bottom side conducts heat into the PCB pad — for sustained repetitive surges, the board copper area under the package sets the effective thermal resistance, not the junction-to-case spec alone. Operating temperature spans -65°C to 150°C junction, covering under-hood automotive ambient and telecom outdoor enclosures without derating concerns at the high end.
Where it fits in the protection scheme
The bidirectional channel protects against both positive and negative transients from a single device — useful on AC-coupled signal lines, bipolar power buses, or data lines where the common-mode voltage can swing either direction. No power line protection rating means it is intended for signal or secondary-side DC rails, not mains AC input stages.