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I have DC simulated the N-33 MOSFET from the UMC_180nm library in Cadence and have found different values of beta effective for different values of Vgs as attached below.

The calculated beta effective from drain current is also not matching with the actual beta effective.

Any help on which beta effective I should choose for further design calculations?

Various mos parameters

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    \$\begingroup\$ I do not know what you mean by "beta effective", so explain it, how is it determined? (perhaps you mean K = Kp * W/L but I still want to see that). \$\endgroup\$
    – Bimpelrekkie
    May 25, 2021 at 13:36
  • \$\begingroup\$ Betaeffective is unCox \$\endgroup\$
    – Supratim Kundu
    May 25, 2021 at 13:36
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    \$\begingroup\$ unCox means nothing to me, add the formula in your question, You can use \$ to make formulas (MathJax). \$\endgroup\$
    – Bimpelrekkie
    May 25, 2021 at 13:38
  • \$\begingroup\$ Do you know the current specified for Vgs(th) \$\endgroup\$
    – Tony Stewart EE75
    May 25, 2021 at 13:42
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    \$\begingroup\$ Maybe you're suffering from short channel effects. What happens if you use devices that are 20/2, 30/3 etc... ? Also, don't expect that these MOSFET's stricktly follow the theoretical Id = Kp * W/L (Vgs - Vt)^2 formula because they just don't. You do get somewhat closer with larger W and L but with modern processes, MOSFETs simply do not have Id ~(Vgs-Vt)^2 behavior. This is due to thin oxides and short channel effects. \$\endgroup\$
    – Bimpelrekkie
    May 25, 2021 at 13:46

1 Answer 1

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Is Vt given at 33nA? If so then Beff from Ids is correct.

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