Protection envelope and what it means for your rail
The 1.5KE220CA-T is a 1500W bidirectional TVS diode (Zener type) that clamps transients on a 185V nominal rail — the reverse standoff voltage is the maximum DC or AC peak the line can carry without the diode conducting leakage. When a surge hits, breakdown starts at 209V minimum and the diode hard-clamps at 328V maximum while shunting 4.6A of peak pulse current in the standard 10/1000µs waveform. That 328V ceiling is the voltage the downstream MOSFET, capacitor, or IC must survive; if your load's abs-max rating is below that, this diode alone won't protect it. With a single bidirectional channel, this one device handles both positive and negative transients on the same line — no need for two unidirectional diodes in anti-series, which saves board area and cuts the parts count on a 185V bus.
Obsolete — sourcing reality for this TVS
Diodes Incorporated lists the 1.5KE220CA-T as obsolete. No factory orders, no last-time-buy window remains open. Supply is limited to surplus and broker inventory held by independent distributors — the date-code mix and lot traceability vary by lot, so each RFQ is confirmed against what is physically available. No official successor order code is published by Diodes; a functional replacement from the same 1.5KE family would require verifying the standoff voltage, clamping, and package match against the BOM's protection requirement.
Package and deployment context
Through-hole DO-201AA / DO-27 axial package — a standard footprint that has been in production for decades. No board-spin risk for a replacement with the same body; the lead spacing and hole diameter are industry-common for this power class.