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ASSURA LVS error | Custom Inductor | Pin mismatch | Unbound devices

pitter

Hi,

I have generated a inductor Ind1 with a Passive Component Designer (PCD) tool. The inductor is used in LC VCO schematic.After LVS run I get the following errors and discrepances:

1)Error: Ind1(Generic) on Schematic is unbound to any layout device
2)in LVS report I get that pins of the inductor are not found in layout, although seen in schematic by the tool.

 I tried to solve problems by:

- adding a line in bind.rul file : 'C Ind1(Generic) Ind1'  what eliminated the error 1), but in the LVS debug tool pin discrepances are found between VCO schematic and layout and Ind1(generated by PCD) schematic and layout.

- used a avCompareRule command indDevice to turn Generic device into inductor IND - still pin mismatch LVS error.

 Any ideas how to solve the problem? Thanks in advance!

Kind Regards,

pitter.

  • Quek

    Hi pitter

    Would you please upload the following files which can be located in the lvs run directory?

    a. design.erc file
    b. design.cls file

    To upload a file, please go to "Options" tab and use the "file attachment" function.

    Thanks
    Quek

  • pitter

    Hi Quek,

     here are the files you asked. They have been generated without adding a line in bind.rul file and using indDevice command.

    Thanks,
    pitter.

    cls_erc_files_pitter.zip
  • Quek

    Hi pitter

    From erc file, we can see the following:

      info: Assign pin label "Pout" at (388.050, -938.250) to layer `net_met2'.
      info: Assign pin label "vdd!" at (1270.800, -927.400) to layer `net_met1'.
      info: Assign pin label "gnd!" at (304.800, -927.050) to layer `net_met1'.
      info: Assign pin label "Mout" at (384.300, -931.250) to layer `net_met1'.
      WARN: Multiple label discarded: "Mout" at (384.300, -931.250) and "Pout" on net C3.
      info: Assign pin label "RestartTrigger" at (1265.650, -940.500) to layer `net_met1'.

    It looks like labels "Mout" and "Pout" might have been mistakenly placed on the same net. Would you please try to correct this? Because both labels are on the same net, Assura discards them and hence results in missing Mout and Pout layout pins.


    Best regards
    Quek

  • tkhan

     There is a section in the VPCM User Guide called "Virtuoso PCD black-box Recognition and Extraction
    Using Assura" which explains how to modify your existing LVS rules to recoginze PCD inductors.

  • pitter

    You are right Quek.

     But the error is caused by the architecture of the differential VCO. Namely the differential output is labeled with pins, that in turn is connected to the spiral. The spiral (there is actually a couple of spirals) is treated by Assura as a typical connection, a short.

    I will get familiar with the suggested section of the VPCD User Guide. I've just only had a brief look on it, it looks like it addresses the issue, but might be challenging. Modifying PDK scripts - I have never done it, but I will give it a try.

    Thanks both of you,

     Take care,
         pitter.

  • pitter

    Hi,

    As for the problem 1) (described in the very first post of this thread), there is a avParameter ?blackBoxCell in the LVS run dialog box. By its means, I can specify the balck box cell (custom inductor Ind1). It solves the problem 1). But I still get errors concerning the unnbound pins between schematic and layout of the inductor.

  • Quek

    Hi pitter

    Would you please post the contents of the erc file?

    Best regards
    Quek

  • snaildr

    Hi Pitter, Quek

     

    Have you figured out about the pin errors? I ran into the same problem...

     

    Thanks,

    Ran 

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