Last-buy window and sourcing posture
The 1.5KE150A-E3/51: Vishay has flagged the 1.5KE150A-/51 as Last Buy, meaning the manufacturer has announced end-of-life and is accepting final orders before production ceases. This is the time to secure lifetime buy quantities or qualify a replacement if the BOM line is not already covered.
The 128 V reverse standoff voltage is the DC or peak-AC level the protected rail can carry without the diode conducting; above that, the device clamps. The 207 V ceiling is the voltage the downstream components must survive during the surge. Unidirectional — one channel, cathode band oriented to the rail, anode to ground. For AC or bidirectional protection, two devices or a bidirectional variant is needed.
Package and thermal envelope
Housed in a DO-201AA (DO-27) axial-lead package, through-hole mounted. The junction temperature range spans -55°C to +175°C, covering industrial and some military-grade thermal environments. Part of the TransZorb series — Vishay's branded TVS family known for tight clamping and fast response. The base product number is 1.5KE150, and this variant ships in bulk packaging.
General-purpose deployment
Listed for general-purpose applications — suitable for overvoltage protection on DC power rails, signal lines, and low-frequency AC circuits where a unidirectional clamp is acceptable.