Protection window and fit check
The 1.5KE56CH: The minimum breakdown voltage is 50.4V, so the protected rail must stay below this level under all normal operating conditions to avoid nuisance clamping. DO-201 (DO-27 axial) through-hole package — the lead spacing and body diameter match standard PCB layouts for 1.5KE-series TVS diodes; no footprint change required if replacing another 1.5KE bidirectional part.
