Clamping voltage and the transient it stops
The 1.5KE550CA: Its 468V reverse standoff voltage means the protected rail can sit at 468V DC or peak AC without the diode conducting leakage; the device starts clamping when the transient exceeds the 522.5V minimum breakdown voltage. At the full 2A peak pulse current (Ipp), the clamping voltage is limited to 760V maximum — this is the voltage the downstream components must survive. The 1500W rating is the product of clamp voltage and Ipp at the test waveform; for shorter pulses the diode can absorb more energy, but the 760V ceiling does not change.
Package and board-fit reality
The DO-201AA (DO-27) axial-lead package is a through-hole format with a 0.052-inch diameter lead. The body length is about 0.4 inches — the leads are formed for through-hole insertion, not surface mount. The 1.5KE series uses tin-plated copper leads rated for the full 1500W pulse without lead fatigue. The DO-201 package dissipates heat through the leads into the PCB copper; a 1-ounce copper trace with at least 0.5-inch lead length per side is typical for the rated power.
Production status and compliance trail
Available in Tape & Reel (TR) or Cut Tape (CT) packaging, which suits both prototype runs and production reels. The base part number 1.5KE covers the full family; the 550CA suffix specifies the 468V standoff bidirectional variant. The General Purpose application class means no automotive (AEC-Q101) or medical-specific qualification is claimed. RoHS and REACH compliance documentation is standard from Littelfuse for this series; the lead-free finish is compatible with standard soldering profiles.