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QRC extraction without LVS first

MoMiner1870

Hello all, is there any way to run QRC parasitic extraction without running LVS first?

I don't have a schematic to run the layout against so LVS will not work.

Thanks!

  • Hi Daryl

    QRC needs the extracted layout netlist so it is always necessary to run LVS or ERC. If a schematic is not available, you can run ERC using PVS. This method enables you to generate spice but not extracted view output.


    Best regards
    Quek

  • Thanks Quek, So if I understand you I need to run ERC, then QRC using the ERC data. This will give me a spice file? Will I still be able to simulate using ADE?

  • Hi Daryl

    When running PVS ERC, please enable "Generate QRC data" option in the form. This will create an "svdb" directory which can be used as input to QRC. You can then generate a spice netlist using QRC. After generating the spice netlist, please create a symbol to represent the netlist so that it can be placed in a schematic for simulation.

    Best regards
    Quek

  • Thanks so much Quek. I will give this a try as soon as possible.
  • Quek, so far this is working fine, but can you help me with getting the spice netlist into a schematic symbol? Or point me to a document that explains it? Thanks again for your help!

  • Hi Daryl

    You can do it as follows:

    a. Open up the spice netlist and note the names of the pins for the top level subckt. E.g. it might be ".subckt myTopCell A B C"
    b. Create a new schematic named "myTopCell" and place 3 pins : A, B and C
    c. Generate a symbol from the schematic and delete the schematic
    d. Copy the symbol as "spectre" view
    e. Open up CDF form for "myTopCell" in "Base" level and go to "spectre" simInfo section
    f. Populate the "termOrder" field with the same name and order as the spice netlist: "A" "B" "C"
    g. Set "Component name" to "myTopCell"
    h. Save and exit CDF form
    i. You are now ready to do spectre simulation. Please remember to include the spice netlist as one of the model files during simulation.

    Best regards
    Quek

  • Quek,  in my .sp file the .subckt line does not have any pins after it.  It just say  .subckt pad_test  and thats it. Above that is .global gnd!

    After that there is a long list of xx23/x0 ect

    Any ideas what I did wrong?

  • Hi Daryl

    You will need to add some some pins to the layout before running PVS ERC and QRC extraction. This means that you need to add labels using the appropriate layer-purpose pairs.

    E.g. add an "ABC" label using layer "M1 pin" or "M1 label" or "M1 drawing", it depends on what the LVS deck needs.

    Best regards
    Quek

  • Thanks Quek I got this working now. I needed to change the pin labels to layer "label". Thanks again for all your help!

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