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ADF4169 PFD Spurs

Question asked by edgin1604 on Apr 11, 2017
Latest reply on May 22, 2017 by edgin1604

Hello!

 

I would like to ask you a question related to PLL ADF4169. I have a signal with frequency of 5 GHz and in wide spectrum there are a lot of strange spurs with PFD frequency. Also i designed loop filter with bandwith 75 kHz and i use PFD frequency 12.5 MHz, the refernce frequency is 25 MHz and in my application only integer mode is used, because of that in R4 I set bits DB[30:26] to 0b01110 . Then I tried to decrease PFD frequncy, these spurs also deacresed in level. What is the nature of noise spurs and what should i do to get rid of that phenomena?    

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