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LMK03328: TICS Pro Configuration Wizard Optimizing

Ryan Larson
Prodigy 80 points

Part Number: LMK03328

Tool/software:

Hello,

I am working on configuring my LMK03328 clock gen in TICS Pro. I am getting a harmonic crosstalk warning between some of my outputs. Is there a way to use these frequencies together so that crosstalk won't be an issue? We have the outputs set as LVDS.

Thanks,

Ryan

  • 0
    TI__Expert 6415 points

    Ryan,

    With this amount of different frequencies, it's almost impossible to completely eliminate crosstalk. However, rearranging the outputs [see below] can help to mitigate it.

    Best,

    Cris

  • 0 in reply to Cris Kobierowski
    Prodigy 80 points

    Hey Cris,

    That makes sense. With this crosstalk, will I be able to rely on the accuracy of the clock outputs? Are they going to be low jitter? How bad will this crosstalk be? Can you give an example of what the harmonic crosstalk would look like? 

    Thanks,

    Ryan

  • +1 in reply to Ryan Larson
    TI__Expert 6415 points

    Ryan,

    Ryan Larson said:
    With this crosstalk, will I be able to rely on the accuracy of the clock outputs?

    Yes, crosstalk does not impact frequency accuracy.

    Ryan Larson said:
    Are they going to be low jitter? How bad will this crosstalk be? Can you give an example of what the harmonic crosstalk would look like? 

    I rearranged the config a bit and attached the results below. Overall, the jitter performance ranges from 125fs to 150fs. This performance will change based on output type and the amount of noise on the reference input. 

    As an example, OUT5 and 6 share a 30MHz spur, likely a harmonic of the 15MHz spur the software predicted. Similarly, OUT4 and 5 share a spur at ~22.5MHz, likely the third harmonic of the 7.5MHz spur the software predicted.

    The software's simulations are not 100% accurate, however they provide a good relative comparison between possible configurations and point out which frequencies to watch for spurs and harmonics.

    LMK03328Crosstalk.zip

    Best,

    Cris