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spurs when using divided by 32 adf4356

Category: Hardware
Product Number: ADF4356

Hi,

i see large spurs when i use output divider /32 or /64 in adf4356.

VCOout is 3840MHz witch divide by 32 will be 120MHz.

f_Refin = 100MHz , R = 1, PFD_Freq = 100MHz.

   Looking forward to your reply.

   Best regards.

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  • Hi Mahdi,

     In the datasheet, figure 11 demonstrates what is the expected harmonics level, you can compare your results with the datasheet values and my measurements. I am also sharing my register settings. you can see harmonics but spurs should be minimal and just around the carrier frequency with a narrow bandwith.  you should check if the bleed current is enabled for the Fractional-N mode. 


    Regards,
    Burhan

Reply
  • Hi Mahdi,

     In the datasheet, figure 11 demonstrates what is the expected harmonics level, you can compare your results with the datasheet values and my measurements. I am also sharing my register settings. you can see harmonics but spurs should be minimal and just around the carrier frequency with a narrow bandwith.  you should check if the bleed current is enabled for the Fractional-N mode. 


    Regards,
    Burhan

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