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AD9910 PLL loop filter

Question asked by mantow on Apr 11, 2014
Latest reply on Apr 14, 2014 by mantow

Hi Engineerzone,


I'd like to ask whether it is possible to configure the PLL on the AD9110 with a loop filter that is higher than 3rd order Type II ?


I understand, from the spreadsheet which ADI provides, that the filter is actually 4th order considering the RC internal to the chip. But I would like to incorporate a much lower cut-off frequency, in order to reduce my reference spurs even more, and hence add my own R and C. If this is not realizable, are there any other Analog Devices DDS which does provide the VCO input out on a separate pin for the user ?


Many thanks