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How to plot Id-Vg at different channel length by cadence spectre ?

richardyuan

Ocean file to plot Id-Vg may like this:

ocnWaveformTool( 'wavescan )
simulator( 'spectre )
design( "xxx")
resultsDir( "xxx" )
modelFile( "xxx")

stimulusFile( ?xlate nil  "xxx")
analysis('dc ?saveOppoint t ?param "Vg" ?start "0" ?stop "3" ?lin "1000" )
desVar( "Vd" 0.1 )
desVar( "Vg" 3.3 )
desVar( "Vs" 0 )
saveOption( 'currents "all" )
temp( 27 )
run()
selectResult( 'dc )
plot(getData("/M0/D") )

Then suppose the nmos instance M0 in the schematic has a CDF parameter "Length" of channel length, how can I get a plot of Id-Vg at different channel length?

Parents

  • Hi Andrew,

    But how can I define a design virable in the Length field of the instance of M0?

    I noticed that I can select the "Component Parameter" l (represent gate length) of M0 when I set "sweep virable" in choosing analysis. And the Vg curve of l sweeping is available by the script:

    analysis('dc ?saveOppoint t ?dev "/M0" ?param "l" ?start "0.2" ?stop "0.6" ?step "0.05" )

    desVar( "Vd" 0.1 )
    desVar( "Vg" 2 )
    desVar( "Vs" 0 )
    saveOption( 'currents "all" )
    temp( 27 )
    run()
    selectResult( 'dc )
    plot(getData("/M0/D") )

    Then I modify my script to  make parametric analysis:

    analysis('dc ?saveOppoint t ?param "Vg" ?start "0" ?stop "2" ?lin "1000" )
    desVar( "Vd" 0.1 )
    desVar( "Vg" 3 )
    desVar( "Vs" 0 )
    desVar( "/M0/l" 0.18 )
    saveOption( 'currents "all" )
    temp( 27 )
    paramAnalysis("/M0/l" ?values '(0.18 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6))

    But Error raised:

    bad name "/M0/l", not added

    The variable "/M0/l" is not defined in the current design.

    What Can I do now? 

Reply

  • Hi Andrew,

    But how can I define a design virable in the Length field of the instance of M0?

    I noticed that I can select the "Component Parameter" l (represent gate length) of M0 when I set "sweep virable" in choosing analysis. And the Vg curve of l sweeping is available by the script:

    analysis('dc ?saveOppoint t ?dev "/M0" ?param "l" ?start "0.2" ?stop "0.6" ?step "0.05" )

    desVar( "Vd" 0.1 )
    desVar( "Vg" 2 )
    desVar( "Vs" 0 )
    saveOption( 'currents "all" )
    temp( 27 )
    run()
    selectResult( 'dc )
    plot(getData("/M0/D") )

    Then I modify my script to  make parametric analysis:

    analysis('dc ?saveOppoint t ?param "Vg" ?start "0" ?stop "2" ?lin "1000" )
    desVar( "Vd" 0.1 )
    desVar( "Vg" 3 )
    desVar( "Vs" 0 )
    desVar( "/M0/l" 0.18 )
    saveOption( 'currents "all" )
    temp( 27 )
    paramAnalysis("/M0/l" ?values '(0.18 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6))

    But Error raised:

    bad name "/M0/l", not added

    The variable "/M0/l" is not defined in the current design.

    What Can I do now? 

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