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Altera_Forum's avatar
Altera_Forum
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16 years ago

PLL Reconfig Icp, R, C Values

Hi,

I am reconfiguring AltPLL (Startix II) to support a range of frequencies based on varying input clock frequency(20 MHz - 180MHz). I could not find in any of the documents the corresponding values for Chargepump current value and Resistance and Capacitance Values for a particular VCO frequency range. I can program these values by taking from megawizard generated PLL files for the corresponding frequency settings. But I ran into problems.

I was hoping that there would be some exact values (Icp, R, C) in one of the documents which I can use to achieve the particular VCO freq.

Appreciate your help if anyone can point me to the right document or can share some thoughts.

Thanks

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    An update on this,

    Got the PLL reconfig working with the values taken from megawizard. If anyone is looking for the same, just writing it down..

    for Stratix II Enhanced PLL Reconfig Values (selected bandwidth auto)

    ----------------------------------

    Freq Icp R C M

    (MHz) (uA) (kOhm) (pF)

    ----------------------------------

    10 52 2.5 5 68

    20 77 1.5 5 32

    30 131 1 16 22

    40 131 1 16 16

    50 110 1 5 12

    60 114 1 5 10

    70 131 1 5 10

    80 114 1 5 8

    90 131 1 5 8

    100 114 1 5 6

    110 114 1 5 6

    120 114 1 5 6

    130 96 1 5 5

    140 72 1 5 4

    150 72 1 5 4

    160 72 1 5 4

    170 72 1 5 4

    180 72 1 5 4