Lifecycle status — obsolete, no direct successor
Littelfuse has marked the 1.5KE56C as obsolete.
Protection envelope — 1500 W peak pulse, 47.8 V standoff
The breakdown voltage range starts at 50.4 V, so the device begins conducting before the rail exceeds the safe operating area of downstream components. A single bidirectional channel protects against both positive and negative surges — useful on AC signal lines or DC rails where polarity reversal is possible, without needing two diodes back-to-back.
Temperature grade and package
The DO-201AA (DO-27) axial-lead package is through-hole mounted, suited for point-to-point wiring or PCB layouts that need a robust mechanical anchor for high-surge paths.