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DAC3482EVM 2-tone test

HENRY JUNG
Expert 2030 points
Other Parts Discussed in Thread: DAC3482

DEARS.

I have a question for operating of DAC3482EVM.

We checked that DAC3482 Evaluation board operation which is used Default Setting guide line in USER_GUIDE.

The end customer need to do 2-tone IMD test DEMO with DAC3482 Evaluation board.

But the operation is not smoothly in DAC3482 Evaluation board.

We need your help about 2-tone test.

Please help to check the following customer requirement.

  1. Need 10MHz interval, 2-tone IMD test result
  2. Need DAC3482 Evaluation board Setting method or Setting file(=Config file)
  • 0
    TI__Guru* 79234 points
    Henry,
    1. The two tone IMD test result can be found on the datasheet, figure15 to figure 19.
    2. The default example configuration file can be found in the software GUI directory:
    C:\Program Files (x86)\Texas Instruments\DAC348x\EVM Configuration File Released\DAC3482
    The example programming requires external 1228.8MHz clock, the DAC3482 is configured with 4x interpolation with NCO set at 30MHz.
    -Kang
  • 0 in reply to Kang Hsia
    Expert 2030 points
    KANG.

    I know the 2-tone test result in Datasheet.
    We need to do 2-tone test with DAC3482EVM.
    Customer would like to know the DAC3482EVM test result.

    Seems that External 1228.8Mhz is wrong data. Need to check whether the clock data is correct or not.
    Please kindly advise if we can do the test of DAC3482EVM as below information.

    1. Input External Clock 122.88Mhz
    2. "DAC3482_FDAC_1228p8MHz_4xint_NCO_30MHz_QMCon" Load
    3. 4x interpolation with NCO set at 30Mhz
    4. Please advise the setting data of "PLL Settings" in DAC3482EVM GUI.
    If "DAC3482_FDAC_1228p8MHz_4xint_NCO_30MHz_QMCon" LOAD, "PLL Settins" will be deactivated.
    5. How should set "PLL Settins" and 2-tone test?
  • 0 in reply to HENRY JUNG
    TI__Guru* 79234 points
    Henry,

    The two tone tests results on the datasheet are measured on the EVM itself.

    To answer your question:
    1. yes, the config file requires external clock of 1228.8MHz of clock. 4x interpolation. This is the final DAC conversion rate.
    The data rate going into the DAC before interpolation is 307.2MSPS.
    2. correct.
    3. correct
    4. external clocking mode is used on the DAC3482. Internal PLL is bypassed. No pll setting required.
    5. PLL setting should be used if the customer wants to use on-chip PLL of the DAC3482. For now, to get a good test setup, I recommend providing external 1228.8MHz clock.

    -Kang
  • 0 in reply to Kang Hsia
    Expert 2030 points

    KANG

    The test results of DAC3482EVM.

    Datasheet reseult and my result are different.

    Need a detail description for my result.

  • 0 in reply to HENRY JUNG
    TI__Guru* 79234 points

    Henry,

    Visiting the DAC3482 datasheet IMD3 result, I saw at 200MHz the IMD3 is around 66dB, which matches your result.

    You may also adjust your spectrum analyzer's attenuation setting to prevent distortion from analyzer itself impacting the measurement. You may need to zoom in on the spurs for finer measurement as noise floor will rise from higher attenuation settings.

    -Kang