What the 1500W peak pulse rating means for your board
The 1.5KE11ARL4G: At the 10/1000µs test waveform it handles 96A peak pulse current before the clamping voltage hits 15.6V — that is the ceiling the downstream IC sees. For a 12V bus under load-dump or inductive kickback, the 10.5V minimum breakdown gives enough margin to avoid nuisance triggering on normal ripple.
Obsolete — sourcing through independent channels
Littelfuse has marked the 1.5KE11ARL4G as Obsolete. For BOM lines that still call this order code, availability is limited to surplus and broker inventory — lot quantities and date codes vary, and each lot is confirmed at RFQ. No pin-compatible direct replacement exists within the Mosorb family that matches the exact 9.4V standoff and 1500W rating in the same DO-201AD package; a board-level substitution would require re-qualifying the clamping voltage and peak current.