ZHCSHN9A February 2018 – April 2018 LMK05028
PRODUCTION DATA.
Each REF-DPLL supports hitless switching through a proprietary phase cancellation scheme, which can be enabled per DPLL. When hitless switching is enabled, it will prevent a phase transient (phase hit) from propagating to the outputs when the two switched inputs have a fixed phase offset and are frequency-locked. The inputs are frequency-locked when they have same exact frequency (0-ppm offset), or have frequencies that are integer-related and can each be divided to a common frequency by integers. When hitless switching is disabled, a phase hit equal to the phase offset between the two inputs will be propagated to the output at a rate determined by the REF-DPLL fastlock bandwidth. The hitless switching specifications (tHITLESS and fHITLESS) are valid for reference inputs with no wander. In the case where two inputs are switched but are not frequency-locked, the output smoothly transitions to the new frequency with reduced transient. Hitless switching is not supported for 1-PPS inputs.