ADRV9003 Reference Clock

Greetings,

  Per the manual, the input Reference clock for this device for a single ended input is between 10MHz and 80MHz.  We selected a 40MHz clock for our AD9364 design.  Now, we are updating this to the ADRV9003.  Based upon board space/size constraints, including availability, we have selected a clock at 49.152Mhz.  Can this frequency be used, and the part can then do the necessary sub-dividing in order to generate the necessary internal frequencies?  Specifically the ADC and Output sample rate.

Thank You for your time and expertise.

Regards,

Stephen Beckwith

  • Hi Stephen,

    Yes, as you have noted your clock frequency is within the accepted range. Additionally I'd like to draw your attention to the section of the user guide titled "DEV_CLK_IN PHASE NOISE REQUIREMENTS", which deals with the phase noise performance required to reach the figures specified on the datasheet.
    Any clock frequency within the advertised range is acceptable, as long as you have also specified that clock frequency within the software.

    Kind Regards,
    Michał

  • Michal;

      Thank you for your speedy reply.  I do, however have a follow up question:

    You stated:  Any clock frequency within the advertised range is acceptable, as long as you have also specified that clock frequency within the software.

    What exactly does this mean?  Is this say a configuration parameter passed during initialization? Or part of the device tree??

    Thank You again!

    Regards,

    Stephen Beckwith

  • Hi Stephen,

    It is passed during initialisation. I suggest you try a demo setup for yourself. This does not require the eval board, and will give you great insight into how the part functions from a software perspective.

    First, download and install the Transceiver Evaluation Software (there is also a link available on the Eval Board page).
    Second, run the TES and click "Use Demo Mode (No Hardware)" on the main screen.
    Third, in the "View" drop-down menu along the top bar, click "Driver Debugger". This will open a new window which shows how your actions in the TES translate into code. You can dock this window for viewing convenience.
    Next, you'll need to go into the "Clocks" section along the left. Here, you can specify the clock frequency you'd like to use, as highlighted in the image below:

    Now click "Program" along the top bar, and you should see various function calls in the Driver Debugger window. You'll even find your specified clock rate (in kHz) being passed near the top.
    Finally, in the "Sample Code" drop-down menu you can select your preferred language to export the code. You can study it to get a closer look at how the device functions, and you can also use it to program your device once you have an eval board using this guide.

    I hope that answers your question.

    Kind Regards,
    Michał