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AD9257 Clock Frequency Value and Data Clock Problem 

Question asked by ErenT on Aug 1, 2018
Latest reply on Aug 1, 2018 by DougI

Hi,

 

I have a AD9257 for analog-digital conversion of my system. I have a clock frequency approiximately 8 MHz for AD9257.

 

AD9257 fco pin works well at 8 MHz clock too. However, dco pin has some unstability at 8 MHz. Also, when I increase clock frequency to 25 MHz dco pin is always 1.8 V.(VDD)

 

Is my usage optimum for AD9257 with 8 or 25 MHz clock? Should I use 40 MHz since ADC has 40 MSPS convertion rate? What can be the reason I cannot see dco signal in my system?

 

Thank you for your attetion.

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