Clamping performance and pulse handling
The 1.5KE20C: This means a 24 V bus sees the clamp engage at roughly 29 V, leaving margin for normal ripple before the TVS conducts. Power line protection is not enabled (No per), meaning this device is intended for secondary-side signal or low-voltage rail clamping rather than mains AC input protection.
Through-hole axial package for board-level retrofit
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE20C mounts through-hole. The axial leads suit point-to-point wiring or PCB layouts where the device is inserted and soldered — common in power supply input stages and telecom line cards. The supplier device package is DO-201, which is the same mechanical outline as the industry-standard DO-201AA. Lead spacing and body dimensions match the 1.5KE series footprint, so a replacement from the same family drops in without layout changes.
Obsolete — sourcing through independent channels
Littelfuse has marked the 1.5KE20C as obsolete. Because the 1.5KE series shares a common DO-201 footprint and similar electrical characteristics across voltage variants, a functionally equivalent TVS from the same family (e.g., a 1.5KE18CA or 1.5KE22CA) may serve as a drop-in replacement if the standoff voltage tolerance is acceptable — verify the breakdown and clamping voltages against the circuit's operating rail before substituting.