AnsweredAssumed Answered

AD9547 sync with Ref

Question asked by kevLove on Feb 19, 2013
Latest reply on Apr 9, 2013 by kevkevkjkj

Hi. I made a board with your AD9547 chip.


My system clock = 1000MHz

DDS = 71.68MHz

Out1 and Out0 = 35.84MHz


Ref = single ended 100KHz ( 2dBm power ) from a signal generator


I am able to see 35.84MHz at Out1 and not at Out0. The reason for this is that I choose to ignore Sync at Out1( I don't check the box in the eval software. When I do check the box for Ignore Sync in the clock distribution section then I see the clock being outputted ).


I don't know why this is needed to output the 35.84MHz. ???


My main question:


I can't make the AD9547 clock output change when I change the REF signal. It doesn't change when I increase the REF output by 100Hz steps. I've tried various loop bandwidths.


Also, Auto sync mode is disabled and sync source is Direct. I've also tried different values for the 'Auto Sync Mode' and 'Sync Source'

Additionally, I've tried different Buildout Thresholds.


My .stp file is attached.




Could someone please tell me what I'm missing to get this working?