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Parasitic exclusion

manudupouy

Hello,

I was using parasitic filter from an extracted view to discover the worst influences. I understood that I could add some parasitics or include all parasitics of an extracted view. So, if I want to simulate my circuit with all parasitic excluding a net, I have to include all parasitics in my constraint window and deactivate the one I don't want. Logic. But, it would be more simple in this case, by default activating all parasitics (without including the long list of parasitcs) and only put in my constraint window the net I don't want the parasitics.

Is it possible?

Emmanuel

Parents

  • Hi,

    One year later. I am back with another problem related to parasitic filter. So, I put it on the same post.

    I don't obtain the same result when I simulate the schematic and the extracted layout where I filtered all parasitics.

    So, could you explain me why such a difference please Andrew?

    It's a real problem for me because I optimized my schematic and was looking for problematic tracks on my layout. My initial step was to begin to simulate the extracted layout without parasitic and add influence of tracks one after one.

    Emmanuel

Reply

  • Hi,

    One year later. I am back with another problem related to parasitic filter. So, I put it on the same post.

    I don't obtain the same result when I simulate the schematic and the extracted layout where I filtered all parasitics.

    So, could you explain me why such a difference please Andrew?

    It's a real problem for me because I optimized my schematic and was looking for problematic tracks on my layout. My initial step was to begin to simulate the extracted layout without parasitic and add influence of tracks one after one.

    Emmanuel

Children
  • in reply to manudupouy

    Hi Emmanuel,

    When you are using parasitic filters to filter all parasitics, you are still using the designed devices from the extracted view. This means that any parameters extracted for those devices, such as ad, as, pd, ps, length-of-diffusion effects, well proximity effects and so on, will have been extracted by your LVS tool. With the schematic, you would (at best) have estimates of those parameters - but they will be different, almost certainly.

    So I wouldn't expect the results to be the same, even if you'd filtered all the parasitic Rs and Cs.

    Regards,

    Andrew.

  • in reply to Andrew Beckett

    Hi Andrew,

    Understood. Thanks a lot for your answer.

    Emmanuel

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