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AMS Unified Netlister with irun cannot handle negative resistance

spike

When I try to run mixed-signal simulation on extracted views that include parasitic resistors the AMS Unified Netlister with irun fails to netlist because there are parasitic resistors with negative resistance values. Contrarily, the OSS-based netlister with irun works.

The negative resistances are generated by Quantus QRC since the command delta_gate_ckt is used.

Tools used:

ICADV12.2-64b.500.7

Calibre LVS v2017.1_17.12

Quantus QRC 16.1.0-p075

Excerpt from failing netlist:

// AMS netlist generated by the AMS Unified netlister
// IC subversion:  ICADV12.2-64b.500.7
// IUS version: 15.10-s027
// Copyright(C) 2005-2009, Cadence Design Systems, Inc
// Design view name: config
// Solver: Spectre

resistor #(.r(62.9496), .c(0)) Rj_3_398 (\129:i_WFBB_RCCAL_DIG_0|I9|clkb , \128:i_WFBB_RCCAL_DIG_0|I9|clkb );
resistor #(.r(-132.1), .c(0)) Rj_3_1038 ();

Excerpt from working netlist:

// AMS netlist generated by the OSS based AMS netlister
// IC subversion:  ICADV12.2-64b.500.7
// IUS version: 15.10-s027
// Copyright(C) 2005-2009, Cadence Design Systems, Inc
// Design view name: config
// Solver: Spectre

resistor #(.r(62.9496), .c(0)) Rj_3_398 (\129:i_WFBB_RCCAL_DIG_0|I9|clkb , \128:i_WFBB_RCCAL_DIG_0|I9|clkb );
resistor #(.r(-132.1), .c(0)) Rj_3_1038 (\22:i_WFBB_RCCAL_DIG_0|I9|clkb , \21:i_WFBB_RCCAL_DIG_0|I9|clkb );

Kind regards, Martin

  • Martin,

    I've tried to reproduce the problem - for me negative resistors (when using the same INCISIVE version and the equivalent IC617 ISR, which should be the same) are netlisted correctly with both the value and connections showing. I'm not using an extracted view, but I don't see why that should matter. Are there any errors shown in the CIW or in the Simulation->Log->Netlister Log when using UNL?

    I also didn't find any reports of a similar problem.

    Probably the best thing to do is to contact customer support so that we can take a look at your data.

    Regards,

    Andrew.

  • Hello Andrew,

    Many thanks for looking into this. I did some additional testing and I found the following:
    1) UNL correctly netlists an analogLib res with negative resistance value, but simultaneously fails on resistors with negative resistance within an extracted view.
    2) UNL appears to fail silently. I have not found any errors reported during netlisting

    I filed the case #46113298

    Kind regards, Martin

  • Martin,

    I picked up that case and have contacted you directly via that.

    Kind Regards,

    Andrew.

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