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AD9959 evaluation board REF_clk problem

Question asked by cscai on Mar 8, 2012
Latest reply on Mar 8, 2012 by DSB

HELLO!

 

    I use AD9959 evaluation board to design signal. when I load the ad9959 software, an error occurs,"the evaluation board doesn't seem to have a ref_clk".

 

   here , I use the 25MHz cystral as  the ref_clk of AD9959. W11 is connected to cystral. the AVDD power is separated from DVDD.

 

   In this mode ,I find the cystral can't generate oscillating signal in the oscillograph. I want to ask whether the C21 ,C22 should be remove from the board.  these two caps will have impacted on cystral signal.

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