• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 22 subscribers
  • Views 748 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CDCE62002: External Loop Filter Component Selection

user4806129
Prodigy 80 points

Part Number: CDCE62002

I'm currently trying to select the values for the external loop filter but I'm unsure as to which tool I should use? The TI webench tool seems to allow for more parameter settings than the CDCE62002 GUI application. What is the best tool to use?

In the GUI application how do I choose the most optimal charge pump current and loop filter bandwidth if multiple settings are OK?

  • 0
    TI__Genius 9920 points
    Hi,
    For starting debug, please adopt GUI recommended setting. The bandwidth (BW) is the most key parameter for the loop filter. You could start from 3mA, 159.154kHz setting. The optimal setting depends on CDCE62002 input reference phase noise. Worse reference need a narrow BW, and better reference could have a wide BW.
    For Icp, bigger value could achieve less noise contribution from PLL, but spurs may be bigger.
    Smaller value would make PLL noise contribution more, but less spurs. Please trade off it by final measurement result.

    Webench provided more flexible settings or solutions. If GUI settings can't get a good result or an clock with enough jitter margin, we will use Webench to find the problem and solution. If you had measured reference clock phase noise, the result could be input into webench for simulate, find a button "Enter Custom Phase Noise for Reference or VCO/VCXO". Then the simulation result would be very close to the real device output.

    Best Regards,
    Shawn