The 1.5KE150CA-E3/54: The 128 V reverse standoff voltage means it sits across a nominal 120 V DC rail or a 120 V AC line without conducting in steady state; the 143 V minimum breakdown triggers clamping at 207 V maximum, shunting up to 7.2 A of surge current away from the protected circuit.
The DO-201AA axial-leaded package (DO-27 equivalent) is a through-hole footprint common in power-supply input stages, telecom line cards, and industrial control boards.
Bidirectional — one device for AC or bipolar lines
The TransZorb series is Vishay's established TVS diode family, known for consistent clamping characteristics and surge robustness across the full temperature range.