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CDCM6208: unlock problem

Kiyoung SON
Intellectual 515 points
Part Number: CDCM6208

Dear TI-er.

My customer is designed his board with cdcm6208.

But, CDCM6208 is unlocked the attached file.

plz help me.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/MLU_5F00_R1_5F00_CDCM6208_5F00_Settings_5F00_1_5F00_122M88.ini

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/MLU_5F00_R1_5F00_CDCM6208_5F00_Settings_5F00_2_5F00_122M88.ini

PLL is locked the attached file.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/MLU_5F00_R1_5F00_CDCM6208_5F00_Settings_5F00_1_5F00_76M8.ini

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/MLU_5F00_R1_5F00_CDCM6208_5F00_Settings_5F00_2_5F00_76M8.ini

  • 0
    TI__Genius 9920 points

    HI Kiyoung,

    All configurations should be optimized by loop filter design. Even you got lock in some setting, CDCM6208 still have risks to be unlocked.

    1, Select button "Loop FIlter" in CDCM6208 EVM GUI.

    2, Input "Phase Margin"  between 45~75 degC

    3, Select " loop bandwidth" ( normally < Phase Detect Frequency / 15 ), if input reference clock is noisy, a narrow loop bandwidth could achieve better jitter performance.

    4, Check "Standard Value"

    5, Put Button "Suggest RC's". You could get new RC's value. If there is no exact R or C in hand, you select a close one. Then press button "Calculate Output (Using RC Input)", to update Phase marging and loop bandwidth, make sure they are still in step 1 & 2 range.

    6, Solder correct C1, R2, C2 on PCB

    Then CDCM6208 is hard to unlock.

    Best Regards,

    Shawn