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LMX2492 / About TICS pro and codeloder

Sho Ogane
Genius 5575 points
Other Parts Discussed in Thread: LMX2492EVM

Hi all.

I evaluated the LMX2492EVM by TICS pro and codeloder.
However the result is defferent.

I set output frequency 9.4GHz.
At TICS pro, Polarity of PhaseDetector&ChargPump is minus(-)
At codeloder, Polarity of PhaseDetector&ChargPump is puls(+)

Why two results are defferent by using TICSpro and Codeloder?
Please check the results and which is result correct?

Best Regards,
Sho

  • 0
    TI__Expert 5370 points

    Dear Sho,

    our apology for the confusion and discrepency between the 2 softwares. They should produce the same result. We are going to fix it.

    The important thing to note is the polarity setting of the register so you have truly the correct feedback on the loop. This is a parameter as the VCO used may have a positive or a negative slope:

    Charge pump polarity is used to accommodate VCO with either polarity so that feedback of the PLL is always correct.

    IF reference (R) output is faster than

    feedback (N) output

    then:

    R28[5]==0 THEN charge pump will source current or labeled as POSITIVE.

    R28[5]==1 THEN charge pump will sink current or labeled as NEGATIVE.

     

    Regards, Simon.

  • 0 in reply to Simon Damphousse
    Genius 5575 points

    Hi Simon,

    Thank you for your reply.
    I understood it!

    Sorry,I have one more question.

    The circuit of LMX2492EVM User's Guide is not same actual EVM.
    The components on the user's guide circuit is not mount on actual EVM.
    So I would like to get the circuit of actual EVM.
    If you have it, please give me.

    Best Regards,
    Sho

  • 0 in reply to Sho Ogane
    TI__Expert 4085 points

    Hi Sho,

    Please look at the attached schematic

    DNP are components that are not populated. As you can see both schematics are the same but, the schematic in the user's guide don't show which components are not populated.

    Thanks,

    Julian

  • 0 in reply to Julian Di Matteo
    Genius 5575 points

    Hi julian,

    Thank you for your information.
    I couldn't see value of the parts.
    So please give me file.

    Best Regards,
    Sho

  • 0 in reply to Sho Ogane
    TI__Expert 4085 points

    Hi Sho,

    I did not realize that the image lost the quality after zooming in.

    Please see attached file.

    LMX2492_DNP_SCHEMATIC.pdf

    Thank you.

    Julian