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What is the difference between DC operating parameters ron and gds of MOS

RFStuff

Dear All,

Cam naybody please tell what is the difference between DC operating parameters ron and gds of MOS.

Is ron=1/gds ?

Kind Regards,



  • Hello RFStuff, it depends on the terminology of your small signal equivalent.

    I added a Small signal equivalent that i use  and the equations that came from it,shown bellow.

    There is no Ron or gds in it.

    If its Ok with Andrew ,can you share the small signal equivalent you are using, so we could find the formulas for ron gds, as the shown bellow parameters  where found.


  • in reply to robert 21

    Actually, they're not quite the same. It depends a bit on the model, but if you look at (say) the bsim4 chapter of the Spectre Circuit Simulator Components and Device Models Reference manual (<SPECTREinstDir>/doc/spectremod/spectremod.pdf) then there are hyperlinks to the equation for gds (12-31 in the Spectre 19.1 documentation) whereas ron is vds/ids (so gds is the small signal conductance, whereas ron is the large-signal resistance at the operating point). 

    I don't think RFstuff's question is related to which small signal equivalent he/she is using - the question is related to the operating point numbers that are produced by spectre.

    Regards,

    Andrew

  • in reply to Andrew Beckett

    Thanks  a lot robert21 and Andrew.

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