The 1.5SMC27A_R1_00001: That 37.5 V ceiling is what the downstream silicon sees — a 24 V rail protected by this part survives a surge that would otherwise punch through a 30 V-rated regulator.
The SMC footprint is larger than the smaller SMA/SMB variants — the extra copper area under the cathode tab pulls heat from the junction during the pulse, which matters for repetitive surge events in an automotive environment.
Automotive application rating suggests the part is qualified for AEC-Q101 or similar stress tests, though the specific automotive-grade certification is not detailed in the available spec fields. The wide temperature range and 1500 W pulse capability align with typical automotive transient protection requirements.