What the protection window means in practice
The 1.5SMCJ16AS_R1_00001: The reverse standoff of 16 V defines the working voltage below which the TVS stays off and draws only leakage current — it must sit above the normal operating rail to avoid clamping during clean operation.
SMC package and board-level fit
With a 150 °C maximum junction temperature and a 1.5 kW transient load, the PCB copper under the device is the primary heatsinking path — undersized pads will push TJ above the rating in sustained surge events. Rated for general-purpose applications with a single unidirectional channel — not a bidirectional part, so polarity matters on DC power rails: cathode faces the line, anode to ground.