The 1.5KE440: Its 376V reverse standoff voltage protects 380V DC rails, and the 632.1V maximum clamping voltage limits the transient to a safe level for downstream semiconductors. The 396V minimum breakdown voltage ensures the device starts conducting before the protected circuit sees a damaging overvoltage. The single unidirectional channel suits DC bus or signal-line clamping where polarity is fixed.
Housed in a DO-201AA / DO-27 axial leaded package, the 1.5KE440 mounts through hole. The axial body and 0.042-inch diameter leads fit standard 0.100-inch pitch PCB layouts or terminal strips. No power line protection rating — this part is intended for secondary-side transient suppression, not direct mains clamping. The 2.5A peak pulse current at 10/1000µs defines the surge capability; derate for shorter pulses per the datasheet curve.
Littelfuse lists the 1.5KE440 as Obsolete. No official successor is recorded. The DO-201 package and 1.5KE series footprint are common, so a parametric substitute (same standoff, similar clamping) may exist; verify the breakdown voltage and pulse rating against the BOM requirement.