Clamping voltage and breakdown margin
The 1.5KE27A B0G: Breakdown occurs between 25.7 V (minimum) and the clamping ceiling of 37.5 V — the 11.8 V window means the TVS starts conducting well before the protected rail sees damaging overvoltage, while the 37.5 V clamp keeps the spike below most 24 VDC-rated semiconductor abs-max ratings. The single unidirectional channel is polarity-sensitive; for AC or bidirectional lines, two devices back-to-back or a dedicated bidirectional part is needed.
Through-hole DO-201 — board-level fit
Housed in a DO-201AA (DO-27) axial-lead package, the part mounts through-hole — the lead bend and hole pattern match the standard 0.100-inch pitch footprint common to legacy and new designs. Bulk packaging means the reel quantity is not fixed; MOQ is by the piece or tube.