Active production — BOM-fit for 468 V rails
The 1.5KE550A: Its 468 V reverse standoff voltage (typ) makes it a fit for protecting 400 VAC nominal DC bus or 480 VAC rectified rails where the steady-state voltage stays below that threshold. The device clamps at 760 V max at 2 A peak pulse current, and breakdown starts at a minimum of 522.5 V. That clamping margin above the standoff gives the protected circuit headroom during transients without nuisance triggering on normal line ripple.
Package and thermal envelope
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE550A is a through-hole part — it fits standard 0.100-inch pitch board layouts and can be hand-soldered or wave-soldered. The supplier device package is DO-201. Operating junction temperature range spans -55°C to 175°C, covering industrial and telecom environments where ambient heat plus self-heating from repeated surges must stay within the die's thermal budget.
Single-channel unidirectional clamping
The 1.5KE550A is a single unidirectional channel — one diode per package, cathode band marked. For bidirectional clamping on AC lines, two devices back-to-back or a dedicated bidirectional variant from the same 1.5KE family would be needed. Peak pulse current capability is 2 A under the 10/1000 µs test waveform, which is the standard TVS rating condition.
Sourcing posture for the 1.5KE550A
The base product number is 1.5KE, so the full reel marking and ordering suffix follow the Littelfuse 1.5KE series convention.