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SpiceIn- MOS size matching problem

MingHChou

Hi,

I'm trying to transfer the spice netlist to schematic, and I adopts the SpiceIn (VirtuosoR 6.1.5).

However, the width and finger width are not the same to the input netlist file.

The following are  netlist and settings.

  • Netlist



  • Spice In setting
    Because I want the Finger Width and Width in CDF parameter to be the same,  I map W to Wfg and W together.
     


  • The SpiceIn.log 





  • Schematic



I found that the Finger width and Width are not the same and not as same as the netlist file, which would lead to LVS (netlist vs. netlist) error .
Could you please let me know if I made something wrong.


P.s. I also tried another version of Virtuoso (6.1.7), and the settings are as same as described before.
Both Width and Finger width are set to the min width of the PDK.
(Length is still correct, i.e. length is as same as netlist file)


Thanks.

  • Quek

    Hi MingH

    This is because you need to trigger the CDF parameters after spice-in. This can be done either using the "Trigger CDF parameter" option in IC617 spiceIn form or the SKILL script in COS article 11018344. Please note that this process might not be so straight-forward.

    Suppose a mos device has the following parameters after spice-in

    w=1u        <=total width value from CDL netlist
    wf=0.1u    <=default finger width value
    nf=2           <=number of fingers

    Using spiceIn trigger CDF option to correct it may result in the following issue:
    => The wrong value of wf is used and we end up with w=0.1u and wf=0.1u. You can try the option first. If it works well, the job is done. If not, you can move on to the next method.

    Create a SKILL procedure which uses the CDF triggering procedure in the COS article. Your SKILL procedure should first assign the correct value to wf. The triggering can then proceed correctly and update the values for the rest of the parameters such as as, ad, ps, pd, etc.


    Best regards
    Quek

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