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WEBENCH® Tools/CDCE62002: VCO Gain

user5850039
Prodigy 215 points

Part Number: CDCE62002

Tool/software: WEBENCH® Design Tools

Hi

I am using WEBENCH sim for CDCE62002.

A defautl value of VCO Gain is 44.1667MHz/V in Loop fileter sim, but the value is valiable .

What value should I input for VCO Gain?

Thank you

  • 0
    TI__Mastermind 28031 points
    Hi,

    I don't see the number in the datasheet, but I think it might reasonable. I did not see a VCO gain number in the datasheet, but I think from section 9.3.5.7.1 "VCO Select", they give a Fmin and Fmax for each VCO band and it looks like about 300 MHz tuning range. So you might think 300/3V ~ 100 MHz, but there could be sub-bands within each of these as they do mention a VCO calibration.

    Clock architect calculates the VCO gain information from the band, so most likely this is right.

    Regards,
    Dean
  • 0 in reply to Dean Banerjee
    Prodigy 215 points

    Hi,

    I tried another tool "CDCE62002 EVM Software", and the VCO gain is fixed value 70MHz/V. I can't change the value.

    What is different between the WEBENCH and CDCE62002 EVM Software?

    Is the specification of CDCE62002  fixed VCO gain? or calculate automatic depends on divider setting and loop filter?

  • 0 in reply to user5850039
    TI__Mastermind 28031 points
    Hi,

    These two pieces of software were done by differnt groups.

    The original CDCE62002 software was done likely by the team that actually developed the CDCE62002 while the WebBench was done by another team, which hopefully got the correct inputs.

    Typically for integrated VCOs, the VCO gain changes as it is lower at the lowest end of the frequeny range (1750 MHz) and highest at the highest end (2336 MHz) Now if you find that the gain according to webbench at 1750 MHz is less than 1750 MHz and the gain at 2336 MHz is greater than 70 MHz, then I would trust webbench because it is taking this into account and assume it to be the more accrate tool.

    REgards,
    Dean