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Using an External Clock with AD9081-FMCA-EBZ


We are trying to get a simple output on one DAC using an external clock fed into the AD9081-FMCA-EBZ and ADS9.  We have followed the datasheets (UG-1829) and have performed the following:

1. Removed C3D and C5D and have populate C4D and C6D with the recommended capacitors (Page 11).

Following the setup on Page 22:

2. Connected the 10MHz references of our two signal generators together (Page 22).

3. Set the input frequency to the AD9081 to 6GHz.

4. Set the input frequency to the ADS9 to 750MHz.

5. Attempted to change the settings so that they match the information on Page 23, but the ACE software reports errors for the JESD interface.  TX Reset Error and occasionally others, particularly on the RX line.

Additional Notes:

1. We don't have any need for the ADCs currently, so we ignored step 4 in the setup process for "Setting up the AD9081 or the AD9082 in full bandwidth mode with external clocking."

2. We are able to get a CW tone out of the DAC using the onboard clock from the HMC chip and an application that we installed following the MxFE_Eval_App_Extras_User_Guide_v1.1.0 document.

3. We want to do this same thing, but with an external clock.

Parents Reply
  • can not ignore Step 4 since providing the Ref Clock to the ADS9 is required for FPGA SERDES PLL to be phase lockd to SERDES PLL on the AD9081.

    Please connect 750 MHz clock source to ADS9V2 ExtClk SMA connector.  Also........the frequency should be set to what the GUI display setting for "Tx Ref Clock" under CLOCK CONFIGURATION.