• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 20 subscribers
  • Views 417 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TRF3765: Phase noise and suprs

toshi-e2e
Genius 4705 points
Part Number: TRF3765

Hi all,

My customer plans to use TRF3765.
Could you please tell me the recommended value of fPDF, NINT, NFRAC  and etc. for minimizing the phase noise and the spurs under the below conditions?

VCO frequency: 3720MHz - 3780MHz

Channel space: 50kHz

RF output frequency: 1/2 VCO frequency

Regards,
Toshi

  • 0
    TI__Mastermind 18065 points
    Toshi:

    I recommend following the loop filter design used on the TI EVM. I recommend operating in fractional mode with as large a PFD frequency as the system can support without exceeding 35 MHz. A value of 30.72 MHz is good. 20 MHz is also acceptable. This means that your reference frequency needs to be a multiple of the pfd (e.g. 61.44 MHz or 40 MHz). The specific value of the R, N, and Nfrac dividers is dependent on the reference frequency and output frequency of choice. The TI EVM will be able to show you the values for a desired output frequency.

    --RJH