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ADF4157 problem

Question asked by fish on Sep 2, 2011
Latest reply on Mar 28, 2013 by rbrennan


I used ADF4157(fractional mode) with OP27 to control the VCO(DCMO190410)

I found that some noise were running on the Fout(desired frequency) its like modulated signal.

my design rule  as below

loop bandwidth=40KHz

phase margin =45 degree

filter type is active filter(inverting input for OP)


Vbias =2.5V ( Non-inverting port)