What the 1500W rating means on a 12V rail
The 1.5KE12C-E3/54: At the clamping voltage of 17.3V max, it shunts up to 86.7A of surge current without failing — enough to absorb a direct lightning-induced transient on a 12V automotive or industrial supply bus before it reaches the downstream regulator. The reverse standoff voltage of 9.72V typ means the diode stays high-impedance below that level, so a nominal 12V rail with normal ripple does not see leakage. Breakdown starts at 10.8V min, clamping at 17.3V max — the window between standoff and clamp is tight enough to protect a 12V-rated IC without nuisance triggering.
Obsolete — sourcing through surplus channels
Vishay lists the 1.5KE12C-/54 as obsolete. The base product number 1.5KE12 identifies the voltage family; the suffix variant (C for bidirectional, for RoHS) is the only differentiator.
Temperature range and mounting
The DO-201AA (DO-27) axial lead package is through-hole, suited for point-to-point wiring or PCB mounting with 0.040-inch diameter leads. The wide temperature envelope means derating is minimal even in a sealed enclosure near a hot power supply. No power line protection feature — this is a signal or low-power rail protector, not a mains-grade MOV replacement.