The 1.5SMC43AT3G is listed as Obsolete by Littelfuse, meaning the manufacturer has discontinued production and there is no official last-time-buy window remaining. Availability is lot-specific and confirmed at RFQ — no stock-holding claim is made here.
1500W surge rating — what it means for the protection window
Breakdown is specified at a minimum of 40.9V, giving a guard band between the standoff and the clamping point. This is a unidirectional Zener TVS — one channel, cathode band oriented, suitable for DC rail protection where the transient polarity is known.
DO-214AB (SMC) — board-fit and thermal notes
The SMC body is larger than the SMA/SMB siblings — it dissipates the 1500W pulse without exceeding the thermal limit, but the board copper area under the terminals still sets the effective RthJA for repetitive events.