Automotive-grade transient suppression for 77.8 V rails
The Vishay 1.5KE91CAHE3_A/C is a bidirectional TransZorb® TVS diode from the automotive-grade 1.5KE series, qualified to AEC-Q101 for use in under-hood and chassis-mounted electronics where load-dump and inductive-switching transients threaten downstream silicon.
What the key ratings mean for the BOM
Breakdown voltage (V_BR) is specified at 86.5 V minimum; this is the voltage at which the device starts to avalanche and conduct significant current. The 125 V clamping voltage (V_C) at 12 A peak pulse current (I_PP) defines the maximum voltage the protected load sees during a surge event — a 125 V clamp on a 77.8 V rail gives roughly 60 % headroom before the protected IC's abs-max rating is reached. AEC-Q101 qualification adds the reliability screening (high-temperature reverse bias, temperature cycling, ESD) that production automotive programs require for PPAP submission.
Housed in a DO-201AA (DO-27) axial-lead through-hole package, the 1.5KE91CAHE3_A/C is designed for hand-insertion or wave-solder assembly. The axial leads carry the full 12 A surge current without fusing, and the body's glass-passivated junction withstands the thermal shock of soldering. The single-channel layout simplifies PCB routing: one series device between the protected rail and ground.
The TransZorb® series carries RoHS compliance and the AEC-Q101 automotive qualification mark. No official pin-compatible second source is recorded on this specific order code; the 1.5KE91CAHE3_A/C is the Vishay-sourced variant for the 77.8 V bidirectional position.