What the 1.5 kW rating means for a 10.2 V rail
The 1.5KE12ARL4G: The breakdown voltage window starts at 11.4 V minimum, so the TVS stays transparent below the rail's normal regulation band and only conducts when a transient pushes the line above that threshold. The 10.2 V reverse standoff is the maximum DC voltage the part blocks without leakage becoming a concern.
DO-201AD axial — what it connects to
Packaged in a DO-201AD axial leaded form factor, the 1.5KE12ARL4G is a through-hole part. The axial leads insert into plated through-holes on the board; the body sits above the PCB, relying on the lead wire and the copper pad area on both sides for heat sinking during the pulse. No exposed pad — the junction-to-ambient thermal path runs through the leads and the solder fillets. The operating junction temperature range spans -65 °C to +175 °C, covering military and industrial thermal profiles. A 175 °C Tj max is typical for silicon avalanche diodes; the derating curve in the full datasheet governs how much peak power is available at elevated ambient temperatures.
Obsolete — what that means for procurement
Sourcing runs through independent surplus and broker channels. Inventory is lot-specific; quantities and date codes are confirmed at the time of an RFQ. No pin-compatible direct replacement from Littelfuse has been published, so a BOM substitution requires a parametric cross-check against the 10.2 V standoff, 1.5 kW pulse rating, and DO-201AD footprint.