1500W Zener TVS for DC rail clamping
The 1.5SMC440: With a 376V reverse standoff voltage and a 632.1V maximum clamping voltage at 2.5A peak pulse current, it protects a single DC rail from transient overvoltage events — typical for 300V nominal bus applications where the clamp triggers before the downstream silicon sees damage.
Breakdown and clamping envelope
Minimum breakdown voltage is 396V, meaning the device starts conducting avalanche current once the rail exceeds that threshold. The clamping ceiling of 632.1V at 2.5A defines the worst-case voltage the protected load sees during a surge — a figure that must stay below the downstream components' absolute-maximum rating.
Obsolete — sourcing via surplus channels
Littelfuse lists the 1.5SMC440 as obsolete. Sourcing runs through independent surplus and auction-lot channels — sealed reels with consistent date-codes from factory-excess buys are the preferred inventory, but each lot is confirmed at RFQ. No pin-compatible direct replacement exists from Littelfuse; a functional substitute would need matching standoff, breakdown, and package footprint, verified against the BOM's clamping requirement.
DO-214AB SMC footprint and board integration
The DO-214AB (SMCJ) surface-mount package is the standard TVS footprint for 1500W class devices. The cathode tab on the unidirectional version is the larger pad — the PCB copper area under the tab sets the thermal impedance for repetitive pulse dissipation. Tape & Reel packaging supports automated pick-and-place; the reel quantity is confirmed at quote.