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LMK04906: LMK04906 STATUS_LD cannot indicate the PLL1&2 look information

Part Number: LMK04906

Tool/software:

Dear team,

Now we use the LMK04906 for our design and we configured our device use the following register value.

R0 (INIT) 0x80160200
R0 0x00140300
R1 0x00140301
R2 0x00140302
R3 0x00143C03
R4 0x00140784
R5 0x80140C85
R6 0x01140006
R7 0x08110007
R8 0x04080008
R9 0x55555549
R10 0x9102412A
R11 0x0401100B
R12 0x1B0C006C
R13 0x3B02848D
R14 0x0240000E
R15 0x8000800F
R16 0xC1550410
R24 0x000000D8
R25 0x02C9C419
R26 0x8FA8001A
R27 0x1900005B
R28 0x0020011C
R29 0x0180031D
R30 0x0200031E
R31 0x001F001F

I think for the PLL1 and PLL2 have been locked after the above configuration. According to my schematic below, the H9 must be on. While now, the H9 is still off.

Could you please help us to double check on your evaluation board?

We use the CLKin2 for the reference with 50MHz sinewave which is coming from the keysight signal generator - N5182B with output power 5dBm.

External VCXO is VX-501-0208-100M0.

  • Hi Brooke, 
    If possible, please share your configuration file as an attachment so I can dump it on EVM. 
    Attach a .tcs file if possible. 
    "File" -> "Save"

    Is LD_MUX set to PLL1&PLL2 DLD with LD_TYPE set accordingly? 

    Best regards, 

    Vicente 

  • Hi Vicente,

    Yes, the PLL1&PLL2 DLD with LD_TYPE  have been set accordingly.

    Please fine the register configuration in .txt file and a .tcs file.

    Thanks for your time.

    lmk04906.txt
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    R0 (INIT) 0x80160200
    R0 0x00140300
    R1 0x00140301
    R2 0x00140302
    R3 0x00143C03
    R4 0x00140784
    R5 0x80140C85
    R6 0x01140006
    R7 0x08110007
    R8 0x04080008
    R9 0x55555549
    R10 0x9102412A
    R11 0x0401100B
    R12 0x1B0C006C
    R13 0x3B02848D
    R14 0x0240000E
    R15 0x8000800F
    R16 0xC1550410
    R24 0x000000D8
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    lmk04906.tcs

    Best Regards,

    Brooke

  • Hi Brooke, 
    I checked on EVM - the LD_MUX functions as expected. I am curious now. 
    if you set the LD_MUX to PLL2 DLD  - is the LED now lit? 
    If the device has been programmed correctly - the VCXO connected to OSCIN will always ensure that PLL2 DLD is high and if that's not the case it's possible the part is not being configured correctly. 
    PLL1 is always more difficult to debug as their are many factors that can contribute to it not locking.

    Regards,

    Vicente 

  • Hi Vicente,

    We have fixed this issue by ourselves.

    We changed the PLL1_WND_SIZE from 40ns to 5.5ns, and the PLL1 has been locked.

    For the PLL1 phase detector freq. is 25MHz in our configuration, and the cycle time is 40ns which is the same time with PLL1 window size. The PLL1 lock counter will increment always. Therefore the PLL1 will never been locked under this condition.

    Thanks for your time. I think we can close this topic.

    Best Regards,

    Brooke