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How to UN-SELECT the noise contribution of a modeled instance with Verilog-A (.va) noise source in its model file

RFStuff

Dear All,

I have some  transistors in my PDK whose model file contains  Verilog-A (.va) noise source .

So when I try to make these Transistor's Noise OFF in Spectre (MMSIM14) option, the noise coming from the Verilog-A (.va) noise source is NOT

getting OFF. In the noise summary it still shows the Noise contribution of these transistors ( basically coming from the Verilog-A noise source).

Is there any way to make the noise of the Verilog-A source OFF ?

Kind Regards,

  • I answered this in a thread of one of your previous posts:

    http://community.cadence.com/cadence_technology_forums/f/33/p/32451/1340993#1340993

    More details can be found in solution 20186436.

    Regards,

    Andrew.

  • Dear Andrew,

    Thanks for the reply.

    I think for Flicker0-Noise source in Verilog-A model the isnoisy is NOT required ?

    Can you please confirm this.

    Kind Regards,

  • Not sure why you think this? It won't disable flicker noise just by setting noiseoff_inst unless the flicker noise is controlled via an isnoisy parameter, or if the coefficients for the flicker_noise function are such that it doesn't output any noise.

    So in my view, you need to implement isnoisy if you want to turn off all noise sources. For example:

    `include "discipline.h"
    `include "constants.h"
    module myres (a,b);

    inout  a,b;
    electrical  a,b;
    branch (a,b) resbr,noisebr;
    parameter real r=1000,m=1,af=2,kf=0;
    parameter isnoisy=1;

    analog begin

      V(resbr) <+ r*I(resbr);
      if (isnoisy) begin
        I(noisebr) <+ white_noise(4*`P_K*$temperature/r);
        I(noisebr) <+ flicker_noise(kf*pow(I(resbr),af),1);
      end

    end

    endmodule

    Regards,

    Andrew.

  • Dear Andrew,

    Thanks for your clarifications.

    Kind Regards,

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