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    vdsat

    In hspice2005.9 and later, for a simple mos transistor simulation, the op has the
    calculation of vod=.. and vdsat=.. they might be considerably different.

    Anyone can tell their difference?

    Thanks in advance.

    Bobxing

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    what is vdsat

    Difference of Vds and Vdsat is Vod. Vds-Vdsat = Vod
    thanks
    -Bharat



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    hspice vod

    You give me a good clue. Thanks
    I studied the simulated list file.

    Vgs-vth=vod,

    But Vds-vdsat <> Vod!
    so how come? the vdsat?



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    vdsat

    For long channel device
    Vod equal to Vdsat

    For short channel device
    There existed a lot of second order effects
    So Vdsat is not simply equal to Vod

    If you want to find out how the hspcie get the vdsat you can refer to the hspice manual, model level.


    While in hand calculte we use vod(vgs - vth) instead of Vdsat to simplified the calculation process.


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    vdsat and vod

    Dear all:

    Please reference this: http://www.ece.uci.edu/docs/hspice/h...001_2-162.html

    If MOS is linear region, vod will closed to vdsat, but when MOS in sat region,
    vod will bigger than vdsat.

    If you use vod to design you circuit, you will get more margin to ensure the mos in sat region when circuit in different corners and temp.


    mpig


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