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AD9525: using the chip as a clock divider only.

Question asked by prup on Aug 5, 2015
Latest reply on Oct 2, 2015 by JLKeip

I am using the AD9525 in divide only mode. The output has two large spurs on either side of the output about 16MHz away, 50dB down. These spurs are killing my SNR. Has anyone seen this? Am I setting something incorrectly? It is independent of the M setting. I do not see these spurs in full PLL mode. I tried using the APLL to turn off the N register and I lowered the CP current to min. No help. I see this output from either the singled-ended output or the differential output.

 

AD9525_divide_only_sw.PNG

AD9525_divide_only.png

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