Hi,

I am using ADF4350 in one of my design. As per datasheet of the ADF4350, we can synthesize any frequency by setting values of INT, FRAC and MOD.

Now

RFout = [INT + (FRAC/MOD)] X fpfd/RFdivider

From this equation it is apparent that synthesized output frequency depends upon ratio FRAC/MOD and not individual values of FRAC and MOD. Now value of **MOD depends upon channel resolution we are willing to achieve.**

Now my question is does lock time depends on selection of values of FRAC and MOD, keeping ratio constant? I mean for example value of FRAC=1 and MOD=10 would generate same frequency as value FRAC=10 and MOD=100(keeping all other values same like INT and fpfd). Does lock time to generate same frequency in both the case would be same? **(it is obvious that channel resolution would be different for both values of MOD=10 and MOD=100. We are not consedered abut channel resolution in this case)**

Thanks & Regards,

Dwijen Pandya

RF Design Engineer,

HCL Technologies

Lock time does not depend in any way on values of FRAC or MOD.