1.5 kW unidirectional Zener TVS — 154 V standoff, 246 V clamp
The 1.5SMC180AS_R1_00001: The breakdown voltage range starts at 171 V minimum, ensuring the device does not conduct during nominal 154 V DC bus conditions. This margin is typical for TVS selection — the standoff voltage must sit above the maximum steady-state rail, and the clamp must stay below the downstream component's absolute maximum rating.
No official second-source or pin-compatible cross-reference is recorded — the part is a standard JEDEC-registered DO-214AB TVS, so parametric equivalents from other manufacturers exist but are not formally listed.