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Custom DC Operating Point Definitions or Overwriting the .dcOpInfo.info file?

CadenceUser3

Our foundry provides a subcircuit model which produces correct ID-VD and ID-VG curves. However, the .OP vdssat (based on BSIM definition) is wildy different than what is expected, ~200mV higher.

What I want:

(1) Custom definition of Vdssat, for example vdssatxxx based on Rout degradation

(2) Must be able to back-annotate on the schematic

One way I was thinking is to run a DC sweep, calculate the value vdssatxxx based on my arbitrary definition, and then overwrite the original .dcOpInfo.info file's vdssat with the the calculated value vdssatxxx from the DC sweep. Now, when I back-annotate it should read the .dcOpInfo.info file that was overwritten.

(1) Is this a reasonable way to do it?

(2) How do I overwrite the existing dcOPInfo.info file (replace vdssat with an arbitrary value that I have calculated)? Does OCEAN have this feature?

(3) Is there a better way to have a custom-defined operating point parameter that can be back-annotated?

Parents

  • A couple of options:

    1. Use opParamExprList in the CDF (search in the documentation for this) to allow you to put an expression in the CDF to compute an operating point value from other values.
    2. In IC616 you can use the Annotation Setup form and enter expressions easily to compute other values (for example, to annotate satMargin by using vds-vdsat). 

    You can't really overwrite the dcOpInfo.info file - I'm not sure you'd want to do that anyway.

    It's not that clear precisely how you want to compute the vdsat from a dc sweep, but I doubt you'd really need to use a dc sweep?

    Andrew.

Reply

  • A couple of options:

    1. Use opParamExprList in the CDF (search in the documentation for this) to allow you to put an expression in the CDF to compute an operating point value from other values.
    2. In IC616 you can use the Annotation Setup form and enter expressions easily to compute other values (for example, to annotate satMargin by using vds-vdsat). 

    You can't really overwrite the dcOpInfo.info file - I'm not sure you'd want to do that anyway.

    It's not that clear precisely how you want to compute the vdsat from a dc sweep, but I doubt you'd really need to use a dc sweep?

    Andrew.

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