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Phase noise of CDCM6208V1EVM

Gk 110
Expert 2440 points
Other Parts Discussed in Thread: CDCM6208V1EVM, CDCM6208

Hello,

Our customer uses CDCM6208V1EVM.
When our customer measured phase noise of CDCM6208V1EVM,
that is different from the data sheet specifications.
Could you please check the attached file?(Phase noise of CMCM6208V1).

Is there something that is considered to be the cause of that?

Our customer has been guessed the crystal mounted on the EVM has been different from that of the circuit diagram.
In the circuit diagram it has become that NX3225SA is mounted.
However, in the photograph it is seen to be the implementation of the different crystal.
Please check the attached file.(Picture of EVM)

Please be converted to ZIP file from Z_I_P.

Best regards,

Manabu ItoFigure of EVM.pdfPhase noise of CDCM6208V1.pdf

  • 0
    TI__Mastermind 24205 points

    Hi Manabu Ito,

    Per the Bill Of Materials, the crystal on the EVM should be NX3225SA 25MHz. In order to help with debugging this issue, please provide me with the following information

    1) CDCM6208 configuration file created using its GUI

    2) Test setup -> Phase Noise Analyzer used, Probes and other relevant setup details.

    Regards

    Arvind Sridhar

  • 0 in reply to Arvind Sridhar
    Expert 2440 points

    Hello Arvind-san

    Thanks for your quick reply.

    I send configration file of CDCM6208.
    Please check the attached file.

    And I wrote about test setup following.

      (Spectrum Analyzer part# & settings)
        - N9020A
           www.keysight.com/.../mxa-signal-analyzer-10-hz-to-265-ghz
        - START FREQ ：100Hz
        - STOP FREQ ：1MHz

     (EVM settings)
       - DVDD         : 3.3V
       - VDD_PLL     : 3.3V
       - VDD_OUTA  : 3.3V
       - VDD_OUTB  : 3.3V
       - VDD_IN       : 3.3V

       - The measured terminal : #26pin(Y4_P)
       - ELF(Loop filter)          :  Setting to FILTER 1
     
    Please let me check again to be sure.
    Is there a possibility that a different crystal from NX3225SA was mounted on the CDCM6208V1EVM?

    Best regards,

    Manabu Ito
     
     testSetting.ini

  • 0 in reply to Gk 110
    TI__Mastermind 24205 points

    Hi Manabu Ito,

    Your PLL configuration looks OK. I was looking over some documentation from Agilent that compares the noise floor of the N9020A MXA phase noise analyzer with the Agilent 5052B that was used for the CDCM6208 phase noise measurement.

    cp.literature.agilent.com/.../5990-5729EN.pdf

    The Phase Noise Floor of N9020A MXA for a 1 GHz carrier measured @ 10kHz offset is ~-115dBc/Hz compared to ~-155dBc/Hz for the 5052B (high correlation). These points will roughly scale down by 20Log(1000/156.25) = ~16dB when measuring a 156.25 MHz carrier. As you can tell, the noise floor of the N9020A will be limiting when measuring the signal that is better than the noise floor of this equipment. Do you have access to Agilent 5052A/B in house? I would start by measuring the phase noise using that instead just so we are not limited by the equipment noise floor.

    Regards

    Arvind Sridhar

  • 0 in reply to Arvind Sridhar
    Expert 2440 points
    Hello Arvind-san

    Thanks for your quick reply.

    I understood your advice.
    But our customer don't have Agilent 5052A/B.
    Could you please try to measure by low noise floor equipment?

    Best regards,

    Manabu Ito