What the 1.5SMC clamping specs mean for your rail
The 1.5SMC9.1CA_R1_00001: The 1.5SMC9.1CA is a unidirectional TVS Zener in the SMC package — it clamps transients on a single polarity rail. At 112 A peak pulse current the clamping ceiling sits at 13.4 V, while the reverse standoff sits at 7.78 V typical — the board rail it protects must run below that standoff level so the device stays invisible until a surge arrives. The 8.65 V minimum breakdown is where conduction begins; the gap between standoff and breakdown gives you the margin before the device engages. If the surge event is brief (10/1000 µs waveform, the standard telecom/industrial transient shape) the device absorbs the energy and returns to its high-impedance state once the event clears. General-purpose classification means it is not radiation-hardened or automotive-qualified out of the box — for those programs the AEC-Q101 grade is the gate.