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Defining length in an expression to be evaluated

canbaltaci

Hello,

While writing an expression for a wave in calculator, I would like to ad the length ot a transistor to the expression. How do I do that?

 Best,

Can

Parents

  • If you are sweeping the length of the transistor in the dc sweep, then there's no need to explicitly save the l, because it's the x-axis of any curve you get. For example:

     //

    model nch bsim4 type=n

    m1 (drain gate 0 0) nch w=20u l=0.8u
    vgs (gate 0) vsource dc=1
    vds (drain 0) vsource dc=1

    dc dc dev=m1 param=l start=0.5u stop=2u step=0.1u

    save drain gate m1:d

    If in ViVA I plot m1:d, it will be versus l. I can always use the xval() function to get a waveform of the xaxis - e.g. xval(i("m1:d" ?result 'dc)) .

    You can save the operating point info from the transistor (e.g. save m1:oppoint) - but since the length or effective length is not part of the operating point (it won't vary with the operating point), it can't be saved - the only time it would vary is as a result of an explicit sweep, in which case it's in the x-axis as I said earlier.

    Regards,

    Andrew.

Reply

  • If you are sweeping the length of the transistor in the dc sweep, then there's no need to explicitly save the l, because it's the x-axis of any curve you get. For example:

     //

    model nch bsim4 type=n

    m1 (drain gate 0 0) nch w=20u l=0.8u
    vgs (gate 0) vsource dc=1
    vds (drain 0) vsource dc=1

    dc dc dev=m1 param=l start=0.5u stop=2u step=0.1u

    save drain gate m1:d

    If in ViVA I plot m1:d, it will be versus l. I can always use the xval() function to get a waveform of the xaxis - e.g. xval(i("m1:d" ?result 'dc)) .

    You can save the operating point info from the transistor (e.g. save m1:oppoint) - but since the length or effective length is not part of the operating point (it won't vary with the operating point), it can't be saved - the only time it would vary is as a result of an explicit sweep, in which case it's in the x-axis as I said earlier.

    Regards,

    Andrew.

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