• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 21 subscribers
  • Views 202 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.

LMX2615-SP: Spurs

Than Nguyen88
Prodigy 30 points
Part Number: LMX2615-SP

I am  using the Pllatinum sim software to estimate Fpd Spurs.  To my surprise, the Fpd spur levels remain the same (-72.8dBc) no matter  what loop filter type (2nd, 3rd or 4th order) I use.  Help please ?

Fpd = 60 MHz, Fout = 480 MHz, VCO1=7680MHz

  • 0
    TI__Genius 11900 points

    Hello Than,

    You can export a PLLATINUM-SIM design using File->Save Design from the tool bar. 

    The Fpd spur is at an offset 60 MHz. This is relatively far out from the loop filter/loop BW and there's not much that can be done to mitigate it.

    Now for example if you change your Fpd = 10 MHz and keep the Fvco and Fout the same you will see a greater effect on the magnitude of the Fpd spur with changing LF.

    It would help if you could share your simulation for further questions so we have a common starting point.

    Thanks,

    Vibhu