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Not able to change output frequency of ADF4351

Question asked by Aamir_Sheikh on Oct 26, 2016
Latest reply on Dec 13, 2016 by rbrennan

Hi, 

 

I am trying to program the ADF4351 and am able to get some output but I'm not able to change the frequency. It is always stuck at 1832MHz no matter what I try.

 

In terms of debug effort, I can confirm that SPI is working because I can control the MUXOUT and the PWRDWN pin configurations. The current consumption is around 80mA I have looked at the LD pin and I am measuring 0V at the output and when I configure the MUXOUT to output the analog lock or digital lock I also get 0V out. So I think the PLL is not locking. How do I go about confirming that the PLL is getting locked?

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