Why a bidirectional CA-suffix Zener TVS sits on data and signal rails
The 1.5SMCJ70CA_R1_00001: The CA polarity code marks it bidirectional — both polarities of transient are clamped symmetrically, which makes it the right choice for AC rails, differential signal pairs, and any node where the bias swings both ways. A unidirectional (single-polarity) TVS would not protect the negative half-cycle, so the bidirectional spec is the first filter on BOM compatibility for any AC-coupled or bipolar node.
