1 Reply Latest reply on Nov 26, 2012 9:50 AM by chris_balcom

    Help needed for property error generated after running lvs


      After running LVS, the following error reported:

      LVS completed. INCORRECT. See report file: lvs. report

      Layout Cell/ Type         Source Cell    Count         Nets          Instances         Ports

      DiodeS                         DiodeS             1            2L, 2S        1L, 1S             2L, 2S

        Discrepancies                                    1

           Property Errors                              1

               Discrepancy #1


      Layout Name                                                                                    Source Name 

      Discrepancy #1 in DiodeS


      Q0(-0.200, 11.200) Q(PNPVERT10)                                                     QQ1 Q(PNPVERT10)

      a : 1 sq u                                                                                           a : 1e+12 sq u


      Netlist Text of layout  


      .SUBCKT DiodeS Vdd Gnd                                                                          

      ** N =2 EP=2 IP=0 FDC =1                                                                                   

      Q0 Gnd Gnd Vdd pnpvert10 AREA=1e-12 $X=-200, $Y=11200 $D=24            



      Netlist of schematic


      subckt DiodeS Gnd Vdd

      QQ1  Gnd Gnd Vdd PNPVERT10 $EA=1

      .ends DiodeS  


      1.What type of property error is this, and how to remove this error?

      For information, using 0.35 AMS PDK(H35), schematic is of diode formed by using PNP VERT10 bipolar transistor.


      please help

        • 1. Re: Help needed for property error generated after running lvs

          I hope someone with more experience using that specific PDK might offer a better answer but in the meantime I can offer some ideas that may help. I suspect that it is a problem of "scaling" with the source netlist or maybe just that one property in the source netlist. I don't see any other devices in the netlist so I don't yet know how the other devices are scaled. My thought is that the other devices may already be scaled and this one particular property might need to be listed as $EA=1u instead of $EA=1. If the problem was more widespread then it may help to add an option to the netlist such as:


          .OPTIONS SCALE=1E-6


          ...but I'm concerned that may result in proper checking of just that $EA property while possibly all the pther properties then become wrong by a similar magnitude. So experiment with that as you see fit.


          Hope it helps,