Clamping performance and protection envelope
The 1.5KE9.1-E3/73: The reverse standoff voltage is 7.37 V, meaning normal DC bus or signal rails up to that level see negligible leakage; breakdown begins at a minimum of 8.19 V.
Sourcing and compliance posture
No official successor or pin-compatible second-source is recorded from Vishay; the 1.5KE series parts are functionally similar but each has unique breakdown and clamping thresholds.
