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AD9767 External Clock Integration in Dual-Port Mode

Category: Hardware
Product Number: AD9767

Hello,

I am working with the AD9767 DAC in Dual-Port Mode using an evaluation board with FPGA integration, and I have encountered an issue. The presence of additional spurious signals in the spectrum of the DAC output is observed depending on the complexity of the FPGA project. However, when I switched to using an external clock source, this issue was resolved.

In my custom design, I intend to use an external clock that is isolated from the FPGA clock, but I am uncertain about how to correctly interface the external clock with both the DAC and FPGA without violating the timing requirements as outlined in the datasheet.

Could you please provide guidance on how to properly implement the external clock for the AD9767 while ensuring the integrity of the timing diagram? I have included my current schematic below for reference.

Thank you.
  

  • Hi  ,

    Thank you for using AD9767.

    Your plan to use a clock buffer to distribute a single clock source to the FPGA and DAC should be okay as long as the devices' input requirements are satisfied and that the PCB layout considerations described in the AD9767 datasheet for these clock inputs are observed to avoid any timing issues.

    Is EVAL-AD9767 the evaluation board you are using? You can use it as a reference to your design as the board provides an option to use a common clock for WRT1, WRT2, CLK1, and CLK2 (see AN-555 p. 3). This should be the same clock source used by the FPGA. See this Wiki user guide for the design files and for further details.

    Hope this helps.

    Regards,
    Zaeefa

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