Breakdown and clamping window
The 1.5SMB23A: The reverse standoff voltage is 20 V — the diode draws negligible leakage below this level, so the protected rail sees no loading during normal operation. Breakdown occurs between 22 V minimum and the clamping ceiling of 33.2 V at full surge current. That 11 V window between breakdown and clamp gives the designer margin to absorb transients without the TVS conducting during nominal voltage ripple. The single unidirectional channel means the cathode is tied to the protected rail and the anode to ground — reverse-polarity protection requires a second device or a series diode upstream.
Package and board integration
The junction operates from -65°C to 150°C, covering the full industrial temperature envelope with margin for self-heating during repetitive surge events. Power line protection is not provided — this part is a Zener TVS, not a crowbar or polyswitch, so it clamps rather than latches. For AC mains or high-energy DC bus protection, a different topology is needed.