b3noi.c

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/**** BSIM3v3.2.4, Released by Xuemei Xi 12/21/2001 ****/

/**********
 * Copyright 2001 Regents of the University of California. All rights reserved.
 * File: b3noi.c of BSIM3v3.2.4
 * Author: 1995 Gary W. Ng and Min-Chie Jeng.
 * Author: 1997-1999 Weidong Liu.
 * Author: 2001 Xuemei Xi
 * Modified by Xuemei Xi, 10/05, 12/21, 2001.
 * Modified bt Paolo Nenzi 2002 and Dietmar Warning 2003
 **********/

#include "ngspice.h"
#include "bsim3def.h"
#include "cktdefs.h"
#include "iferrmsg.h"
#include "noisedef.h"
#include "suffix.h"
#include "const.h"  /* jwan */

/*
 * BSIM3noise (mode, operation, firstModel, ckt, data, OnDens)
 *    This routine names and evaluates all of the noise sources
 *    associated with MOSFET's.  It starts with the model *firstModel and
 *    traverses all of its insts.  It then proceeds to any other models
 *    on the linked list.  The total output noise density generated by
 *    all of the MOSFET's is summed with the variable "OnDens".
 */

/*
 Channel thermal and flicker noises are calculated based on the value
 of model->BSIM3noiMod.
 If model->BSIM3noiMod = 1,
    Channel thermal noise = SPICE2 model
    Flicker noise         = SPICE2 model
 If model->BSIM3noiMod = 2,
    Channel thermal noise = BSIM3 model
    Flicker noise         = BSIM3 model
 If model->BSIM3noiMod = 3,
    Channel thermal noise = SPICE2 model
    Flicker noise         = BSIM3 model
 If model->BSIM3noiMod = 4,
    Channel thermal noise = BSIM3 model
    Flicker noise         = SPICE2 model
 */

extern void   NevalSrc();
extern double Nintegrate();

/* 
 * The StrongInversionNoiseEval function has been modified in
 * the release 3.2.4 of BSIM3 model. To accomodate both the old
 * and the new code, I have renamed according to the following:
 *
 *
 * BSIM3v3.2.4 -> StrongInversionNoiseEvalNew
 * Previous    -> StrongInversionNoiseEvalOld
 *
 * 2002 Paolo Nenzi
 */

/*
 * JX: 1/f noise model is smoothed out 12/18/01.
 */

double
StrongInversionNoiseEvalNew(double Vds, BSIM3model *model,
			    BSIM3instance *here, double freq, double temp)
{
struct bsim3SizeDependParam *pParam;
double cd, esat, DelClm, EffFreq, N0, Nl;
double T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, Ssi;

    pParam = here->pParam;
    cd = fabs(here->BSIM3cd);
    esat = 2.0 * pParam->BSIM3vsattemp / here->BSIM3ueff;
    if(model->BSIM3em<=0.0) DelClm = 0.0; 
    else { 
	    T0 = ((((Vds - here->BSIM3Vdseff) / pParam->BSIM3litl) 
	    	+ model->BSIM3em) / esat);
            DelClm = pParam->BSIM3litl * log (MAX(T0, N_MINLOG));
    }
    EffFreq = pow(freq, model->BSIM3ef);
    T1 = CHARGE * CHARGE * 8.62e-5 * cd * temp * here->BSIM3ueff;
    T2 = 1.0e8 * EffFreq * here->BSIM3Abulk * model->BSIM3cox
       * pParam->BSIM3leff * pParam->BSIM3leff;
    N0 = model->BSIM3cox * here->BSIM3Vgsteff / CHARGE;
    Nl = model->BSIM3cox * here->BSIM3Vgsteff
    	  * (1.0 - here->BSIM3AbovVgst2Vtm * here->BSIM3Vdseff) / CHARGE;

    T3 = model->BSIM3oxideTrapDensityA
       * log(MAX(((N0 + 2.0e14) / (Nl + 2.0e14)), N_MINLOG));
    T4 = model->BSIM3oxideTrapDensityB * (N0 - Nl);
    T5 = model->BSIM3oxideTrapDensityC * 0.5 * (N0 * N0 - Nl * Nl);

    T6 = 8.62e-5 * temp * cd * cd;
    T7 = 1.0e8 * EffFreq * pParam->BSIM3leff
       * pParam->BSIM3leff * pParam->BSIM3weff;
    T8 = model->BSIM3oxideTrapDensityA + model->BSIM3oxideTrapDensityB * Nl
       + model->BSIM3oxideTrapDensityC * Nl * Nl;
    T9 = (Nl + 2.0e14) * (Nl + 2.0e14);

    Ssi = T1 / T2 * (T3 + T4 + T5) + T6 / T7 * DelClm * T8 / T9;
    return Ssi;
}

/*
 * The code for releases: BSIM3V32, BSIM3V322, BSIM3V323
 * follows
 */

double
StrongInversionNoiseEvalOld(double vgs, double vds, BSIM3model *model,
			    BSIM3instance *here, double freq, double temp)
{
  struct bsim3SizeDependParam *pParam;
  double cd, esat, DelClm, EffFreq, N0, Nl, Vgst;
  double T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, Ssi;

  pParam = here->pParam;
  cd = fabs (here->BSIM3cd);
  /* Added revision dependent code */
  if (model->BSIM3intVersion < BSIM3V323)
  {
    if (vds > here->BSIM3vdsat)
    {
      esat = 2.0 * pParam->BSIM3vsattemp / here->BSIM3ueff;
      T0 = ((((vds - here->BSIM3vdsat) / pParam->BSIM3litl) +
  	   model->BSIM3em) / esat);
      DelClm = pParam->BSIM3litl * log (MAX (T0, N_MINLOG));
    }
    else
      DelClm = 0.0;
  }
  else
  {
    if (model->BSIM3em <= 0.0)	/* flicker noise modified -JX */
      DelClm = 0.0;
    else if (vds > here->BSIM3vdsat)
    {
      esat = 2.0 * pParam->BSIM3vsattemp / here->BSIM3ueff;
      T0 = ((((vds - here->BSIM3vdsat) / pParam->BSIM3litl) +
  	   model->BSIM3em) / esat);
      DelClm = pParam->BSIM3litl * log (MAX (T0, N_MINLOG));
    }
    else
      DelClm = 0.0;
  }
  EffFreq = pow (freq, model->BSIM3ef);
  T1 = CHARGE * CHARGE * 8.62e-5 * cd * temp * here->BSIM3ueff;
  T2 = 1.0e8 * EffFreq * model->BSIM3cox
     * pParam->BSIM3leff * pParam->BSIM3leff;
  Vgst = vgs - here->BSIM3von;
  N0 = model->BSIM3cox * Vgst / CHARGE;
  if (N0 < 0.0)
      N0 = 0.0;
  Nl = model->BSIM3cox * (Vgst - MIN (vds, here->BSIM3vdsat)) / CHARGE;
  if (Nl < 0.0)
      Nl = 0.0;

  T3 = model->BSIM3oxideTrapDensityA
     * log (MAX (((N0 + 2.0e14) / (Nl + 2.0e14)), N_MINLOG));
  T4 = model->BSIM3oxideTrapDensityB * (N0 - Nl);
  T5 = model->BSIM3oxideTrapDensityC * 0.5 * (N0 * N0 - Nl * Nl);

  T6 = 8.62e-5 * temp * cd * cd;
  T7 = 1.0e8 * EffFreq * pParam->BSIM3leff
     * pParam->BSIM3leff * pParam->BSIM3weff;
  T8 = model->BSIM3oxideTrapDensityA + model->BSIM3oxideTrapDensityB * Nl
     + model->BSIM3oxideTrapDensityC * Nl * Nl;
  T9 = (Nl + 2.0e14) * (Nl + 2.0e14);

  Ssi = T1 / T2 * (T3 + T4 + T5) + T6 / T7 * DelClm * T8 / T9;
  return Ssi;
}



int
BSIM3noise (int mode, int operation, GENmodel *inModel, CKTcircuit *ckt,
	    Ndata *data, double *OnDens)
{
BSIM3model *model = (BSIM3model *)inModel;
BSIM3instance *here;
struct bsim3SizeDependParam *pParam;
char name[N_MXVLNTH];
double tempOnoise;
double tempInoise;
double noizDens[BSIM3NSRCS];
double lnNdens[BSIM3NSRCS];

double vgs, vds, Slimit;
double T1, T10, T11;
double Ssi, Swi;

double m;

int i;

    /* define the names of the noise sources */
    static char *BSIM3nNames[BSIM3NSRCS] =
    {   /* Note that we have to keep the order */
	".rd",              /* noise due to rd */
			    /* consistent with the index definitions */
	".rs",              /* noise due to rs */
			    /* in BSIM3defs.h */
	".id",              /* noise due to id */
	".1overf",          /* flicker (1/f) noise */
	""                  /* total transistor noise */
    };

    for (; model != NULL; model = model->BSIM3nextModel)
    {    for (here = model->BSIM3instances; here != NULL;
	      here = here->BSIM3nextInstance)
	 {    pParam = here->pParam;
	      switch (operation)
	      {  case N_OPEN:
		     /* see if we have to to produce a summary report */
		     /* if so, name all the noise generators */

		      if (((NOISEAN*)ckt->CKTcurJob)->NStpsSm != 0)
		      {   switch (mode)
			  {  case N_DENS:
			          for (i = 0; i < BSIM3NSRCS; i++)
				  {    (void) sprintf(name, "onoise.%s%s",
					              here->BSIM3name,
						      BSIM3nNames[i]);
                                       data->namelist = (IFuid *) trealloc(
					     (char *) data->namelist,
					     (data->numPlots + 1)
					     * sizeof(IFuid));
                                       if (!data->namelist)
					   return(E_NOMEM);
		                       (*(SPfrontEnd->IFnewUid)) (ckt,
			                  &(data->namelist[data->numPlots++]),
			                  (IFuid) NULL, name, UID_OTHER,
					  (void **) NULL);
				       /* we've added one more plot */
			          }
			          break;
		             case INT_NOIZ:
			          for (i = 0; i < BSIM3NSRCS; i++)
				  {    (void) sprintf(name, "onoise_total.%s%s",
						      here->BSIM3name,
						      BSIM3nNames[i]);
                                       data->namelist = (IFuid *) trealloc(
					     (char *) data->namelist,
					     (data->numPlots + 1)
					     * sizeof(IFuid));
                                       if (!data->namelist)
					   return(E_NOMEM);
		                       (*(SPfrontEnd->IFnewUid)) (ckt,
			                  &(data->namelist[data->numPlots++]),