Obsolete — but still a solid clamp for legacy boards
The 1.5KE68AG: It clamps at 92V maximum and has a 58.1V reverse standoff — meaning it stays out of the way below that and only starts conducting when a transient pushes past it.
What the ratings mean for your protection design
Breakdown voltage is 64.6V minimum — that is the point where the Zener starts to conduct. Operating temperature spans -65°C to 175°C junction — wide enough for outdoor or industrial gear that sees cold starts and hot enclosures. The DO-201AD axial-lead package is through-hole, so it is a field-swappable part if you have a soldering iron and a desoldering pump in the kit.
Sourcing an obsolete TVS — what to expect
Because Littelfuse has marked this Obsolete, there is no factory lead time or authorized-channel stock. No pin-compatible drop-in replacement from the same manufacturer is listed, so if the board needs this exact clamp voltage and package, the existing stock is the only source.