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CDCI6214: How to specify the numerator and denominator of the FOD on the ClockPro GUI

user4779049
Expert 2155 points
Part Number: CDCI6214
Other Parts Discussed in Thread: LMK03328

Please advise me on a question bellow:

I want to generate 148.5 MHz and 148.35174 MHz from 27 MHz reference
using CDCI6214 enabling fractional divider in it.
I have chosen the 2700 MHz VOC frequency. So the input frequency
is one eighth (337.5MHz)
So, 145.5 MHz and 148.35174 MHz can be obtained by divided by
44/1000 and 440/1001 respectively.
However, I do not know how to specify numerator and denominator
In the Clock Pro GUI.

The GUI suggested the numerator and denominator itself.
However, there is small frequency error.
I need to specify the precise numerator and denominator.

Mita

  • 0
    TI__Expert 5325 points

    Hello Mita,

    this device has a fixed denominator, you can only adjust the numerator. There will always be a slight frequency error.

    Please find the best solutions below for 27 MHz reference:

    VCO in MHz 148 + 1/2 MHz 148 + 32/91 MHz
    Offset in ppm fod_msb fod Offset in ppm fod_msb fod
    2673 0 40960 0 0.006797 41033 373
    2754 -0.002337 43194 93 0.006988 43270 74
    2794.5 0.009214 44311 140 -0.00567 44388 180

    (with fod_clk_chX=IODX)

    Best regards,

    Patrick

  • 0 in reply to Patrick Kammermayer
    Expert 2155 points

    Patrik-san,

    Thank you for the answer.

    I undestand that in order to fill my request, I need to use other solution such as LMK03328.

    Mita