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about CDF parameters...

tkhan

Here's my situation: Say I make a schematic of an inverter, and the W and L are pPar() parameters so I can define them when the symbol is added to another schematic. Now I make a schematic with 3 inverter symbols all of different W and L, and I make corresponding layout - how can I do LVS in this case since the W and L are parameters? I found that for a single symbol and its corresponding layout, I could change the Base CDF parameters to match the W and L of the layout, but when there are 3 instances that way doesn't make sense. Any suggestions, if this is even possible?

I'm working with an old PDK which only has Diva rules.

  • Andrew Beckett
    If you're doing the LVS at the level where you have the three inverters, it should just work - no need to worry about changing the base CDF of the inverter cell. That would only be an issue if you were trying to LVS one of the inverters.

    I'm assuming you have CDS_Netlisting_Mode set to Analog so that Diva LVS is using the auLvs netlister (so that the pPar's are being understood by the netlister)? If so, all should work fine. If it doesn't, you probably need to provide more details as to what doesn't work...

    Regards,

    Andrew
  • tkhan

     Thanks Andrew, you were right I just ran an LVS with 3 different inverters and it passed without modifying the Base CDF parameters. As you mentioned I did have to change it for a single instance when I tried a few days back, and I was curious how it would work in the case of multiple instances with different sizes.

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