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LMX2582EVM: RF & microwave forum

Preethi J
Prodigy 90 points
Part Number: LMX2582EVM

Tool/software:

Hi Team, 

I'm using the PLLatinum SIM to simulate a loop filter for LM2582 at 2.45GHz to have as much low Jitter as possible. I see two optimizations for Jitter - Optimize Jitter and Jitter Clean. Can you please let me know the difference between the two? I notice changes in phase margin and Gamma when I toggle between these two parameters. Could you please elaborate on Optimize Jitter and Jitter Clean?

Thank you,

Preethi

  • 0
    TI__Mastermind 26991 points

    Hi Preethi,

    Optimize jitter will result in lowest jitter possible.

    Jitter cleaning applications are for when the reference clock is dirty and you need to “clean” it. This results in the most narrow loop bandwidth possible since the close in phase noise from an extremely clean source such as a TCXO/OCXO will always dominate the overall phase noise.

    What is your ref clk for your application?

    Regards,

    Vicente

  • 0 in reply to vicente flores prado
    Prodigy 90 points

    Hi Vincente, 

    Thanks for your reply. My ref clock is around 100MHz. I'm choosing XO but my requirement is to have lowest jitter. Do you think I should go in for a OCXO instead? 

    Also, I have another question related to the filter: For an N order filter, why do I see N+1 poles after simulation in the PLLatinum SIM tool? Is this due to internal circuitry in the IC? 

    Best,

    Preethi

  • 0 in reply to Preethi J
    TI__Mastermind 26991 points

    Hi Preethi,

    if you wish to have best jitter performance possible a TCXO/OCXO will have best performance over an XO.

    That is correct, the device has integrated caps.

    Regards,Vicente