Surge rating and protection window
The 1.5KE200-B: Its 180V minimum breakdown voltage means the device starts conducting just above the normal operating level, and the 287.7V maximum clamping voltage at 5.5A peak pulse current (10/1000µs waveform) defines the voltage the downstream circuitry must survive. The 5.5A peak pulse current rating is the current the diode can handle at the clamping voltage for the standard 10/1000µs surge — a typical lightning or inductive-load transient. For a 171V rail, the 180V breakdown provides a guard band against normal line ripple and tolerance.
Package and board integration
Housed in a DO-201AA (DO-27) axial-leaded through-hole package, the 1.5KE200-B mounts with the cathode band oriented per the circuit polarity — this is a unidirectional device, so reverse-voltage protection is not built in. The axial leads suit point-to-point wiring or PCB through-holes; the DO-201 body is larger than the smaller DO-41 or SMA packages, which means higher surge capacity at the cost of board space. The wide range also means no derating is needed for most outdoor telecom or power-supply applications.
Sourcing an obsolete TVS diode
For a BOM line locked to this order code, the sourcing path is the surplus and broker market. The 1.5KE series is a long-running TVS family, so inventory of this voltage variant still circulates. Expect to verify date code and lot traceability at quote; no manufacturer warranty applies through non-authorized channels.