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LMK04610: calculating the loopbandwidth

gurudatta p
Prodigy 20 points

Part Number: LMK04610

  1. LMK04610 is not shown in Pllatinum SIM software, so how to calculate loopbandwidth,
    In Tic's pro they are just asking to mention bandwidth 
    image.png
  2. why pllatinum sim does't have lmk04610, then how to get overall phase noise and rms jitter
  • 0
    TI__Guru** 119750 points

    Hi There,

    The loop filter in LMK04610 is a semi-digital filter, TICS Pro already support the loop filter design, so there is no need to put the simulation in PLL Sim.

    To do the design, setup the R div, N div and frequencies properly. Then input the VCXO gain and desired bandwidth, click the Find PLL1 Settings button, TICS Pro will select the Charge pump setting for you. 

  • 0 in reply to Noel Fung
    Prodigy 20 points

    Hi Noel,

    1. Like loop bandwidth changes based on my phase noise of my input and vcxo so then how does software get to know were to set to get optimum phase noise 
    2. output of this , I am feeding to another lmx as an input, so how to get phase noise plot of LMK04610

  • 0 in reply to gurudatta p
    TI__Guru** 119750 points

    Hi There,

    PLL1 is used as a jitter cleaner, the output phase noise is basically equal to the phase noise of the VCXO, as long as the loop bandwidth is very small.

    Typical loop bandwidth for this application is below 20Hz.

    If the loop bandwidth is 20Hz, then the phase noise of PLL1, after 20Hz, is equal to VCXO phase noise.

    You can also use any loop bandwidth you want, just tell TICS Pro and click the Find PLL1 Settings button.

    For example, 100Hz bandwidth.

    10Hz bandwidth.