Voltage selection and clamping behaviour
The 1.5KE27C-B: The 23.1 V reverse standoff voltage (working voltage) means this part protects a 24 V bus or a 24 Vdc supply rail — the TVS remains transparent below that level and only conducts when the transient exceeds the breakdown threshold of 24.35 V min. Maximum clamping at 39.38 V keeps the protected circuit's downstream components within a safe voltage ceiling; a 40.5 A peak pulse current at that clamp voltage confirms the 1500 W rating holds across the full pulse envelope.
Temperature range and deployment context
The DO-201 package body and axial leads handle the thermal cycling of soldered through-hole joints better than a small SMD package in high-vibration environments — a consideration for power supplies, base stations, and heavy equipment control boards.
Littelfuse lists the 1.5KE27C-B as obsolete. A design-in replacement would require a board spin — the DO-201 footprint is not shared by surface-mount TVS diodes in the same voltage class.