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LMX1204: Difference between production and preliminary virsion:

Shehzad Rasheed
Prodigy 10 points

Part Number: LMX1204

I have a custom board design with an LMX1204 chip, if I look at the chip it has P as a postfix (LMX2594P), so I assume it is a preliminary version of LMX1204. I used the TicsPro Ver 1.7.2 which programmed the part successfully. I was not able to program the chip on the newer board and observed that the chip doesn't have the P as a postfix, so I assume it is production version. Now I am using the TicsPro Ver 1.7.5.15 to program the production version chip but for some reason, it never gives the output. The following are the questions:

1 - Am I using the correct version of TicsPro that I was supposed to use?

2 - Are there any other modifications between preliminary and production chips other than the register map?

3 - I have verified the input clock signal and power supplies for the LMX1204 chip they all are good. What else I should look for?

4 - Are there any known issues with the LMX1204P (Preliminary) oscillating?

Thanks,

Shehezad

  • 0
    TI__Mastermind 35040 points

    1) The latest version of TICS Pro should work with parts marked "LMX1204". If there's a prefix P ("PLMX1204") this may be a preproduction sample that has a different register map; an older version of the device profile would be required, and I may be able to provide that as a discrete profile for the latest version of TICS Pro over E2E if required. I'm slightly concerned that you describe a device with a postfix P, as I don't recognize this from our initial prototypes... Can you please confirm that you see a postfix P instead of a prefix P?

    2) There were a few fixes between prerelease silicon and final silicon:

    • 3dB phase noise degradation in buffer mode corrected
    • Buffer mode no longer has high-frequency oscillation spurs - the root cause was eliminated
    • Multiplier has complete frequency range coverage from 3.2 GHz to 6.4 GHz
    • Some common mode voltage and current issues were resolved in the SYSREF outputs
    • Multiplier ratios are 1 + CLK_MULT value instead of just CLK_MULT value
    • The register map shifted around a whole lot, such that prior register configs are effectively incompatible with the current register map

    3) Are you trying to use the old .TCS file from TICS Pro 1.7.2 in the new version of TICS Pro? Since this file is now incompatible, special handling would be required to update the config in that file with the correct register settings. Can you upload the TCS file you're currently using for review by TI, and clearly indicate which version of the software generated the file we're reviewing?

    4) Preproduction LMX1204 definitely had an input buffer oscillation issue that would put random high-frequency spurs on buffer mode inputs. Final silicon corrected this defect as mentioned in response to (2).

  • 0 in reply to Derek Payne
    Prodigy 10 points

    Thank you for your answers:
    1 - The chip has the prefix P. I just confirmed it, so you are correct.

    3 - I am using TicsPro Ver 1.7.2 for the chip that has the prefix P, and using TicPro Ver 1.7.5.15 for the one without the prefix P. Please find the attached files for LMX1204 and PLMX1204 files have the TicPro Version mentioned in the filename. 

    2 & 4 - Thank you for clarification on the oscillation issue.

    Looking forward to hearing back.

    Thank you,

    Shehzad

    PLMX1204_ver1p7p2p00.tcs

    LMX1204_ver1p7p5p15.tcs

  • 0 in reply to Shehzad Rasheed
    TI__Mastermind 28031 points

    We tested your configuration in the lab.  We have a version P silicon and your version 1.7.2 file worked on that.

    We also have a production silicon board and your default file did not work, but we were able to set this up with divide by 4.

    So there seems to be some issue with the settings for the settings in your TicsPro Ver 1.7.5.15 file, but we need some more time to figure this out

  • +1 in reply to Dean Banerjee
    TI__Mastermind 28031 points

    Also, I set up a TICSPRO file using the GUI so it matched what you had.  And it worked.  So maybe one of those registers that needs to be programmed, but are set to 1's and 0's (undisclosed engineering bits) was off.  In either case, try this one and we can use this one for comparision as this works on my setup and your other file does not.

    WorkingLMX1204.tcs

  • 0 in reply to Dean Banerjee
    Prodigy 10 points


    I appreciate the swift assistance provided regarding this issue. The attached files have worked for me, allowing me to adjust the divider values as needed, and they now function as expected.

    I am currently utilizing the LMX1204 to generate clocks for the JESD204C link on our custom boards. I have two versions of these boards, with the only difference being the presence of either the PLMX1204 or the LMX1204 component. The JESD204C functionality is operating smoothly on the board featuring the PLMX1204. However, we are encountering difficulties on the board equipped with the LMX1204. I have removed all clock delays from the configuration file, setting all delays to zero. I suspect that the LMX1204 may exhibit a distinct phase relationship between sysref and clocks, which might be contributing to the issue.

    If you could provide any guidance or insights on this matter, especially considering the only difference is the LMX1204 part, I would greatly appreciate it. I want to extend my sincere thanks for the help you've already provided.

    Thanks,
    Shehzad