What the key ratings mean for your BOM
The 1.5SMBJ12CA-H: The 12 V reverse standoff voltage means this TVS sits across a 12 V rail and will not conduct leakage current under normal operation — it only starts to clamp when the line exceeds that threshold.
The DO-214AA (SMB) package is a standard surface-mount footprint — the same as many other SMB TVS diodes, so the layout is interchangeable with other parts in this package if a second-source is needed. It is a single bidirectional channel in one package, meaning it protects against both positive and negative transients on the same line without needing two diodes back-to-back.
It is part of the Bourns 1.5SMBJ series which includes AEC-Q101 automotive qualification, so the documentation typically includes the AEC-Q101 test report and RoHS/REACH compliance statements from the manufacturer.