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Need a quick explanation for back annotating parasitics in IC6.1.4

bnugent

Hi folks,

 

 

I am currently working on properly back annotating parasitics from the av_analog_extracted view onto the schematic for convenience. But does anyone have any quick tips on how to do this?
 
I am using IC6.1.4, Assura  4.12, and QRC 9.14.
 
Thanks

 

  • Hi bnugent

    You can refer to $CDSHOME/doc/parasim/parasim.pdf. The manual explains specifically about post layout simulation and backanotation.

    1. Create schematic
    2. Create test-bench using schematic
    3. Create config view for test-bench
    4. Create layout
    5. Run Assura LVS
    6. Run QRC parasitic extraction to generate extracted view
    7. Open up config view and switch to extracted view
    8. Open up test-bench from config view
    9. Run spectre simulation
    10. Descend into the subcell schematic from the test-bench schematic
    11. Display parasitics menu from "Launch" menu
    12. Set up parasitics info and do backannotation


    Best regards
    Quek

  • Hi Quek, 

     

    Thanks for the speedy response Quek. I figured this out, however for larger designs, when I select the "Show Parasitics"  after launching the parasitics tab within the subcell I want; the resistances all come up as r = NA.

     When I do smaller cells I have no problem with back annotation. Any pointers for larger design?

     

    And I will check that document out.

     

    -Brian 

  • Brian,

    You have to do a DC spectre simulation in order for it to be able to compute the effective R for the net.

    Regards,

    Andrew
  • Hi Andrew, Do you mean that I need to a DC spectre simulation at the subcell I am interested in and then do DC sims all the way up to the top level ? Thanks, Brian
  • Brian,

    What I mean is that you need to do a DC simulation in spectre using the extracted view you're trying to show the parasitics from. When you do Parasitics->Setup, it will also have a path to sim results, if I remember correctly, but this would normally be auto-populated if you pushed down from the sim testbench.

    This is covered in the documentation (sorry, I'm having to do this from memory as I'm on the move)

    Regards,

    Andrew

  • Andrew,

     

    I see. My path to the sim results was not auto-populating (another issue for another time). You and Quek both told me that the documentation covers this. Could you explicity tell me which document it is when you get a chance. This would be extremely helpful.

     

     Cheers,

     

    Brian 

  • Hi Brian

    As stated in my initial reply, the manual is located at $CDSHOME/doc/parasim/parasim.pdf. "$CDSHOME" refers to the shell variable which contains the path to your IC614 installation. The installation contains a "doc" directory. Please look for parasim directory in the doc directory.


    Best regards
    Quek

  • Quek, I have the literature now and it made everything more clear. My issue was... When I descended into the symbol (of the TB) and opened up the schematic and Launch-> Parasitics-> Setup the path to the DCop data was not automatically loaded. Thanks for the help Cheers, Brian
  • Andrew, I found the documentation and I can now successfully back annotate the parasitics. The path to the DCop info did not automatically load when you set up the parasitics from the config view. Thanks for the help. Cheers, Brian

  • Brian

    Could you give me a the path of DCop? 

    I need it for annotating R value.

    Thanks

    Soroosh 

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