The 1.5KE350C-E3/54: With a 284 V reverse standoff, the diode stays transparent below that DC bias — no leakage impact on the protected line under normal operating conditions. The 504 V clamp at 3 A means a transient exceeding the breakdown threshold (315 V min) is clamped to 504 V, protecting downstream silicon rated for that peak voltage.
DO-201 axial package — through-hole board integration
The 1.5KE package code indicates the same body size as the rest of the 1.5KE series, so the PCB layout is consistent across the voltage range.