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ADF5355 phase shift while in FRAC Mod

Question asked by stepro on Mar 30, 2017
Latest reply on Apr 3, 2017 by MRichardson

Hi,

we use the ADF 5355 on the EV-ADF5355SD1Z Eval-Board. Synchronous to our reference signal we like to generate a signal of the same frequency as the reference. Of that signal we want to adjust the phase in relation to the reference. In order to use the phase adjust we cannot work with INT mode.  With the settings below we should be able to reach to goal. But:

The board indicates a locked PLL but the frequencies are not synchronized, they slowly drift apart (a couple of degrees each second). When I decrease FRAC2 by 1 the drift is reduced to a couple of degrees an hour.

Phase shift doesn`t work correctly. Try to shift with any value even 0 or 180 degrees (phase value 0 or 8388608) once or repeatedly produces stochastic, not reproducible resulting phase shifts.

What`s the solution to this?  

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