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Replace schematic design variable SKILL

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In our analog design flow, our designers utilize design variables in their schematics during the design process to help with optimization. These variables can appear at the top-level or in sub-cells of the hierarchy. Once the design is finished, designers have two options: 1. Go back and manually update all instances that use variables with the correct values. This is a manual error-prone step 2. Save the design variables to the cellview property bag and hope that works with the rest of the design flow I'm currently looking into a third option, where I automate the "hardening" of the design variables at the end of optimization by use of a SKILL script that can go through the hierarchy and replace the variables with fixed values. Before I re-invent the wheel, I wanted to know if there are any other ways to deal with this issue or if someone had already created a solution for this problem. I'm guessing this is a common problem for anyone utilizing variables for optimization, so would be grateful for any input with regard to best practices or SKILL suggestions
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  • One thing they could do is to not add design variables for the things they wish to vary, but in ADE XL you can use the "Variables and Parameters Assistant" - on the parameters tab, you can select instances in your schematic (which can be in lower level blocks, even readonly blocks) and override the values. You can even set up that some of the parameters are matched or ratio matched this way (so you only need to vary one of them). You can even set up sweeps on these. All of this can be done without touching the schematic - and is also the same way that you set up the ranges for parameters to be varied in the optimizers in the GXL tier.

    Once you have a result you're happy with (either by manual optimization, or by automatic optimization), you can use the right mouse button menu over the specific result you're satisfied with, and backannotate the results (which will update the values on the schematic(s).

    If you're not familiar with the features of ADE XL and GXL, it's probably worth contacting your local Cadence office - maybe somebody could give you a brief overview?

    Regards,

    Andrew.

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  • One thing they could do is to not add design variables for the things they wish to vary, but in ADE XL you can use the "Variables and Parameters Assistant" - on the parameters tab, you can select instances in your schematic (which can be in lower level blocks, even readonly blocks) and override the values. You can even set up that some of the parameters are matched or ratio matched this way (so you only need to vary one of them). You can even set up sweeps on these. All of this can be done without touching the schematic - and is also the same way that you set up the ranges for parameters to be varied in the optimizers in the GXL tier.

    Once you have a result you're happy with (either by manual optimization, or by automatic optimization), you can use the right mouse button menu over the specific result you're satisfied with, and backannotate the results (which will update the values on the schematic(s).

    If you're not familiar with the features of ADE XL and GXL, it's probably worth contacting your local Cadence office - maybe somebody could give you a brief overview?

    Regards,

    Andrew.

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