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ADF4351 - How to control output phase?

Question asked by SR8151 on Dec 18, 2012
Latest reply on Dec 20, 2012 by icollins

I need to control the output phase of the ADF4351 relative to the input reference.  I need help because I have not yet found the register settings to do this.  I am using the ADF4351 to synthesize 50 MHz from a 25 MHz reference clock.  I need to be able to program the phase relationship between the 25 MHz reference clock and 50 MHz output in 4000 increments using the 12-bit phase word.  I am using the ADF4351 Eval Board, but have not been able to find a setup that allows me to control the output phase. 


The first image below shows my overall setup, but the GUI has changed some of my actual settings.


Actual settings:

INT = 127

MOD = 4000

I set the phase word from 0 to 3999 in an attempt to change the phase, but this does nothing to the output.

The actual register settings cannot be depicted in the ADI GUI, so I have shown them in hex below.


Can anyone advise me on how to set the chip up to get control of the output phase?


Steve, Colorado Springs, CO