Transient suppression for general-purpose lines
The 1.5KE120CA-E3/51: Housed in the DO-201AA (DO-27) axial-lead package, it mounts through-hole and suits general-purpose transient suppression in power supplies, industrial controls, and telecom equipment where a single bidirectional device replaces two unidirectional diodes in antiparallel.
The 114V minimum breakdown voltage ensures the device starts conducting before the protected circuitry sees damaging overvoltage. At the 165V clamp, the 9.1A peak pulse current is the maximum the diode can handle in the 10/1000µs test waveform — a shorter pulse (e.g. 8/20µs) allows a higher peak current, but the 1500W peak power rating is the hard ceiling for any pulse shape.
Last Buy — what it means for procurement
Vishay lists the 1.5KE120CA-/51 as Last Buy. Sourcing is through independent distribution channels — quantities and pricing are confirmed at RFQ against the BOM line. For a last-time-buy part, the buyer should verify the required quantity and order buffer stock if the design has no drop-in alternative. The DO-201AA footprint is common across the 1.5KE series, so a parametric cross to a different voltage grade (e.g. 1.5KE110CA or 1.5KE130CA) may work if the protection threshold shifts are acceptable — but no direct pin-compatible replacement is documented.