Automotive-grade TVS with a 1500 W pulse rating
The 1.5KE30AHE3/51 is a unidirectional TransZorb® TVS diode from Vishay's Automotive series, qualified to AEC-Q101 for use in under-hood and chassis-domain electronics. The DO-201AA (DO-27) axial-lead package is a through-hole form factor common in power-supply input stages and junction-box protection modules.
Clamping voltages and breakdown margin
Breakdown occurs at a minimum of 28.5 V, giving a 2.9 V margin above the 25.6 V standoff — this ensures the diode stays off during normal battery voltage swings but fires before the downstream silicon sees damaging overvoltage. The 36.2 A peak pulse current capability (10/1000 µs) handles the energy from a typical alternator load-dump event on a 24 V system. No power-line protection (bidirectional) is offered — this is a unidirectional clamp intended for DC rails where the cathode is tied to the positive bus and the anode to ground. The single-channel layout matches a single supply-rail protection zone.
Obsolete — sourcing through independent channels
Vishay has marked the 1.5KE30AHE3/51 as obsolete. No pin-compatible direct replacement from Vishay's current TransZorb portfolio is documented — a board-level substitution would require validating the DO-201AA footprint and the 1500 W pulse rating against an active alternative.