hfetload.c

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            *(ckt->CKTstate0 + here->HFETAvgspp) = vgspp;
            *(ckt->CKTstate0 + here->HFETAvgdpp) = vgdpp;
            *(ckt->CKTstate0 + here->HFETAcg)    = cg;
            *(ckt->CKTstate0 + here->HFETAcd)    = cd;
            *(ckt->CKTstate0 + here->HFETAcgd)   = cgd;
            *(ckt->CKTstate0 + here->HFETAcgs)   = cgs;
            *(ckt->CKTstate0 + here->HFETAcgspp) = cgspp;
            *(ckt->CKTstate0 + here->HFETAcgdpp) = cgdpp;
            *(ckt->CKTstate0 + here->HFETAgm)    = gm;
            *(ckt->CKTstate0 + here->HFETAgds)   = gds;
            *(ckt->CKTstate0 + here->HFETAggs)   = ggs;
            *(ckt->CKTstate0 + here->HFETAggd)   = ggd;
            *(ckt->CKTstate0 + here->HFETAggspp) = ggspp;
            *(ckt->CKTstate0 + here->HFETAggdpp) = ggdpp;
            *(ckt->CKTstate0 + here->HFETAgmg)   = gmg;
            *(ckt->CKTstate0 + here->HFETAgmd)   = gmd;            

            /*
             *    load current vector
             */
load:

            m = here->HFETAm;

            ceqgd = model->HFETAtype*(cgd+cgdpp-ggd*vgd-gmg*vgs-gmd*vds-ggdpp*vgdpp);
            ceqgs = model->HFETAtype*(cgs + cgspp - ggs*vgs - ggspp*vgspp);
            cdreq = model->HFETAtype*(cd + cgd + cgdpp - gds*vds - gm*vgs);            
            *(ckt->CKTrhs + here->HFETAgatePrimeNode) += m * (-ceqgs-ceqgd);
            ceqgd = model->HFETAtype*(cgd-ggd*vgd-gmg*vgs-gmd*vds);
            *(ckt->CKTrhs + here->HFETAdrainPrimeNode) += m * (-cdreq+ceqgd);
            ceqgd = model->HFETAtype*(cgdpp-ggdpp*vgdpp);
            *(ckt->CKTrhs + here->HFETAdrainPrmPrmNode) += m * ceqgd;
            ceqgs = model->HFETAtype*(cgs-ggs*vgs);
            *(ckt->CKTrhs + here->HFETAsourcePrimeNode) += m * (cdreq+ceqgs);
            ceqgs = model->HFETAtype*(cgspp-ggspp*vgspp);
            *(ckt->CKTrhs + here->HFETAsourcePrmPrmNode) += m * ceqgs;
                    
            /*
             *    load y matrix 
             */

            *(here->HFETAdrainDrainPtr)               += m * (model->HFETAdrainConduct);
            *(here->HFETAsourceSourcePtr)             += m * (model->HFETAsourceConduct);
            *(here->HFETAgatePrimeGatePrimePtr)       += m * (ggd+ggs+ggspp+ggdpp+gmg+model->HFETAgateConduct);
            *(here->HFETAdrainPrimeDrainPrimePtr)     += m * (gds+ggd-gmd+model->HFETAdrainConduct+model->HFETAgf);
            *(here->HFETAsourcePrimeSourcePrimePtr)   += m * (gds+gm+ggs+model->HFETAsourceConduct+model->HFETAgi);
            *(here->HFETAsourcePrmPrmSourcePrmPrmPtr) += m * (model->HFETAgi+ggspp);
            *(here->HFETAdrainPrmPrmDrainPrmPrmPtr)   += m * (model->HFETAgf+ggdpp);
            *(here->HFETAdrainDrainPrimePtr)          -= m * (model->HFETAdrainConduct);
            *(here->HFETAdrainPrimeDrainPtr)          -= m * (model->HFETAdrainConduct);
            *(here->HFETAsourceSourcePrimePtr)        -= m * (model->HFETAsourceConduct);
            *(here->HFETAsourcePrimeSourcePtr)        -= m * (model->HFETAsourceConduct);
            *(here->HFETAgatePrimeDrainPrimePtr)      += m * (-ggd+gmd);
            *(here->HFETAdrainPrimeGatePrimePtr)      += m * (gm-ggd-gmg);
            *(here->HFETAgatePrimeSourcePrimePtr)     -= m * (ggs+gmg+gmd);
            *(here->HFETAsourcePrimeGatePrimePtr)     += m * (-ggs-gm);
            *(here->HFETAdrainPrimeSourcePrimePtr)    += m * (-gds-gm+gmg+gmd);
            *(here->HFETAsourcePrimeDrainPrimePtr)    -= m * (gds);
            *(here->HFETAsourcePrimeSourcePrmPrmPtr)  -= m * (model->HFETAgi);            
            *(here->HFETAsourcePrmPrmSourcePrimePtr)  -= m * (model->HFETAgi);
            *(here->HFETAgatePrimeSourcePrmPrmPtr)    -= m * (ggspp);
            *(here->HFETAsourcePrmPrmGatePrimePtr)    -= m * (ggspp);
            *(here->HFETAdrainPrimeDrainPrmPrmPtr)    -= m * (model->HFETAgf);
            *(here->HFETAdrainPrmPrmDrainPrimePtr)    -= m * (model->HFETAgf);
            *(here->HFETAgatePrimeDrainPrmPrmPtr)     -= m * (ggdpp);
            *(here->HFETAdrainPrmPrmGatePrimePtr)     -= m * (ggdpp);
            *(here->HFETAgateGatePtr)                 += m * (model->HFETAgateConduct);
            *(here->HFETAgateGatePrimePtr)            -= m * (model->HFETAgateConduct);
            *(here->HFETAgatePrimeGatePtr)            -= m * (model->HFETAgateConduct);
            

        }
    }
    return(OK);
}




static void leak(double gmin, double vt, double v, double rs, double is1, double is2,
                 double m1, double m2, double *il, double *gl)

{

  double vt1 = vt*m1;
  double vt2 = vt*m2;

  if(v > -10*vt1) {
    double dvdi0;
    double iaprox;
    double iaprox1;
    double iaprox2;
    double v0;
    double vteff = vt1 + vt2;
    double iseff = is2*pow((is1/is2),(m1/(m1+m2)));
    if(rs > 0) {
      double unorm = (v + rs*is1)/vt1 + log(rs*is1/vt1);
      iaprox1 = vt1*diode(unorm)/rs - is1;
      unorm = (v + rs*iseff)/vteff + log(rs*iseff/vteff);
      iaprox2 = vteff*diode(unorm)/rs - iseff;
    } else {
      iaprox1 = is1*(exp(v/vt1) - 1);
      iaprox2 = iseff*(exp(v/vteff) - 1);
    }
    if((iaprox1*iaprox2) != 0.0)
      iaprox = 1./(1./iaprox1 + 1./iaprox2);
    else
      iaprox = 0.5*(iaprox1 + iaprox2);
    
    dvdi0 = rs + vt1/(iaprox+is1) + vt2/(iaprox+is2);
    v0    = rs*iaprox;
    v0   += vt1*log(iaprox/is1 + 1) + vt2*log(iaprox/is2 + 1);
    //*il   = __max(-is1,iaprox + (v - v0)/dvdi0)*0.99999;
    *il   = MAX(-is1,iaprox + (v - v0)/dvdi0)*0.99999;
    *gl = 1./(rs + vt1/(*il+is1) + vt2/(*il+is2));
  } else {
    *gl = gmin;
    *il  = (*gl)*v-is1;
  }

}





static void hfeta(HFETAmodel *model, HFETAinstance *here, CKTcircuit *ckt,
                  double vgs, double vds, double *cdrain, double *gm,
                  double *gds, double *capgs, double *capgd,
                  double *cgd, double *gmg, double *gmd,
                  double *cgs, double *ggs)

{
           
  double vt;
  double vgt;
  double vgt0;
  double sigma;
  double vgte;
  double isat;
  double isatm;
  double ns;
  double nsm;
  double a;
  double b;
  double c;
  double d;
  double e;
  double f;
  double g;
  double h;
  double p;
  double q;
  double s;
  double t;
  double u;
  double nsc = 0.0;
  double nsn = 0.0;
  double temp;
  double etavth;
  double gch;
  double gchi;
  double gchim;
  double vsate = 0.0;
  double vdse;
  double cg1;
  double cgc;
  double rt;
  double vl;
  double delidgch;
  double delgchgchi;
  double delgchins;
  double delnsnsm;
  double delnsmvgt;
  double delvgtevgt = 0.0;
  double delidvsate;
  double delvsateisat;
  double delisatisatm;
  double delisatmvgte;
  double delisatmgchim;
  double delvsategch;
  double delidvds;
  double delvgtvgs = 0.0;
  double delvsatevgt = 0.0;

  vt     = CONSTKoverQ*TEMP;
  etavth = ETA*vt;
  vl     = VS/TMU*L;
  rt     = RSI+RDI;
  vgt0   = vgs - TVTO;
  s      = exp((vgt0-VSIGMAT)/VSIGMA);
  sigma  = SIGMA0/(1+s);
  vgt    = vgt0+sigma*vds;
  u      = 0.5*vgt/vt-1;
  t      = sqrt(model->HFETAdeltaSqr+u*u);
  vgte   = vt*(2+u+t);
  b      = exp(vgt/etavth);
  if(model->HFETAeta2Given && model->HFETAd2Given) {
    nsc    = N02*exp((vgt+TVTO-VT2)/(ETA2*vt));
    nsn    = 2*N0*log(1+0.5*b);
    nsm    = nsn*nsc/(nsn+nsc);
  } else {
    nsm = 2*N0*log(1+0.5*b);
  }
  if(nsm < 1.0e-38) {
    *cdrain = 0;
    *gm = 0.0;
    *gds = 0.0;
    *capgs = CF;
    *capgd = CF;
    goto cgd_calc;
  }
  c      = pow(nsm/NMAX,GAMMA);
  q      = pow(1+c,1.0/GAMMA);
  ns     = nsm/q;
  gchi   = GCHI0*ns;
  gch    = gchi/(1+gchi*rt);
  gchim  = GCHI0*nsm;
  h      = sqrt(1+2*gchim*RSI + vgte*vgte/(vl*vl));
  p      = 1+gchim*RSI+h;
  isatm  = gchim*vgte/p;
  g      = pow(isatm/IMAX,GAMMA);
  isat   = isatm/pow(1+g,1/GAMMA);
  vsate  = isat/gch;
  d      = pow(vds/vsate,M);
  e      = pow(1+d,1.0/M);
  delidgch      = vds*(1+TLAMBDA*vds)/e;
  *cdrain       = gch*delidgch;
  delidvsate    = (*cdrain)*d/vsate/(1+d);
  delidvds      = gch*(1+2*TLAMBDA*vds)/e-(*cdrain)*
                  pow(vds/vsate,M-1)/(vsate*(1+d));
  a             = 1+gchi*rt;
  delgchgchi    = 1.0/(a*a);
  delgchins     = GCHI0;
  delnsnsm      = ns/nsm*(1-c/(1+c));
  delvgtevgt    = 0.5*(1+u/t);
  delnsmvgt     = N0/etavth/(1.0/b + 0.5);
  if(model->HFETAeta2Given && model->HFETAd2Given)
    delnsmvgt     = nsc*(nsc*delnsmvgt+nsn*nsn/(ETA2*vt))/((nsc+nsn)*(nsc+nsn));
  delvsateisat  = 1.0/gch;
  delisatisatm  = isat/isatm*(1-g/(1+g));
  delisatmvgte  = gchim*(p - vgte*vgte/(vl*vl*h))/(p*p);
  delvsategch   = -vsate/gch;
  delisatmgchim = vgte*(p - gchim*RSI*(1+1.0/h))/(p*p);
  delvgtvgs     = 1-vds*SIGMA0/VSIGMA*s/((1+s)*(1+s));
  p             = delgchgchi*delgchins*delnsnsm*delnsmvgt;
  delvsatevgt   = (delvsateisat*delisatisatm*(delisatmvgte*delvgtevgt +
                  delisatmgchim*GCHI0*delnsmvgt)+delvsategch*p);
  g             = delidgch*p + delidvsate*delvsatevgt;
  *gm           = g*delvgtvgs;
  *gds          = delidvds + g*sigma;

  // Capacitance calculations
  temp          = ETA1*vt;
  cg1           = 1/(D1/EPSI+temp*exp(-(vgs-IN_VT1)/temp));
  cgc           = W*L*(CHARGE*delnsnsm*delnsmvgt*delvgtvgs+cg1);
  vdse          = vds*pow(1+pow(vds/vsate,MC),-1.0/MC);
  a             = (vsate-vdse)/(2*vsate-vdse);
  a             = a*a;
  temp          = 2.0/3.0;
  p             = PM + (1-PM)*exp(-vds/vsate);
  *capgs        = CF+2*temp*cgc*(1-a)/(1+p);
  a             = vsate/(2*vsate-vdse);
  a             = a*a;
  *capgd        = CF+2*p*temp*cgc*(1-a)/(1+p);
/*
  {
  char buf[128];
  FILE *fp;
  fp = fopen("d:\\temp\\debug.txt","at");
  sprintf(buf,"%f\t%f\t%e\t%e\n",vgs,vds,W*L*CHARGE*delnsnsm*delnsmvgt*delvgtvgs,cgc);
  fputs(buf,fp);
  fclose(fp);
  }
*/  
cgd_calc:

  if(model->HFETAgatemod != 0) {
    // Gate-drain current calculation
    double vkneet;
    double vmax;
    double td;
    double delcgdvgs;
    double delcgdtd;
    double deltdvdse;
    double deltdvkneet;
    double delvdsevmax;
    double delvdsevds;
    double dvdsevgs;
    double dvdsevds;
    double dtdvgs;
    double dtdvds;
                 
    vkneet = CK1*vsate+CK2;
    vmax   = CM1*vsate+CM2;
    a      = pow(vds/vmax,MT2);
    b      = pow(1+a,1/MT2);
    vdse   = vds/b;
    c      = pow(vdse/vkneet,MT1);
    d      = pow(1+c,1/MT1);
    td     = TEMP+TALPHA*vdse*vdse/d;
    e      = CONSTKoverQ*td*M2D;
    p      = PHIB/(CONSTboltz*td);
    f      = exp(-p);
    q      = (vgs-vdse)/e;
    g      = exp(q);
    h      = ISO*td*td*f*g;
    *cgd   = h - ISO*TEMP*TEMP*exp(-PHIB/(CONSTboltz*TEMP));
    delcgdvgs   = h/e;
    delcgdtd    = h*(p-q+2)/td;
    deltdvdse   = TALPHA*vdse*(2-c/(1+c))/d;
    deltdvkneet = (td-TEMP)*c/((1+c)*vkneet);
    delvdsevmax = vdse*a/((1+a)*vmax);
    delvdsevds  = (1-a/(1+a))/b;
    temp        = delvsatevgt*delvgtvgs;
    dvdsevgs    = delvdsevmax*CM1*temp;
    dtdvgs      = deltdvdse*dvdsevgs+deltdvkneet*CK1*temp;
    *gmg        = delcgdvgs+delcgdtd*dtdvgs;
    temp        = delvsatevgt*sigma;
    dvdsevds    = delvdsevds+delvdsevmax*CM1*temp;
    dtdvds      = deltdvdse*dvdsevds+deltdvkneet*CK1*temp;
    *gmd        = -delcgdvgs*dvdsevds+delcgdtd*dtdvds;
  } else {
    gmg = 0;
    gmd = 0;
  }  

  if(model->HFETAgatemod != 0) {  
    // Gate-source current calculation
    double evgs;
    double vtn = vt*M2S;
    double csat = ISO*TEMP*TEMP*exp(-PHIB/(CONSTboltz*TEMP));
    if (vgs <= -5*vt) {
      *ggs = -csat/vgs+ckt->CKTgmin;
      *cgs = (*ggs)*vgs;
    } else {
      evgs = exp(vgs/vtn);
      *ggs = csat*evgs/vtn+ckt->CKTgmin;
      *cgs = csat*(evgs-1)+ckt->CKTgmin*vgs;
    }
  }

  if(model->HFETAgatemod != 0 && (A1 != 0.0 || A2 != 0.0)) {
    // Correction current calculations  
    double vmax;
    double delvdsevmax;
    double delvdsevds;
    double dvdsevgs;
    double dvdsevds;
    vmax        = CM3*vsate;
    a           = pow(vds/vmax,MV1);
    b           = pow(1+a,1/MV1);
    vdse        = vds/b;
    delvdsevmax = vdse*a/((1+a)*vmax);
    delvdsevds  = (1-a/(1+a))/b;
    dvdsevgs    = delvdsevmax*CM3*delvsatevgt*delvgtvgs;
    dvdsevds    = delvdsevds+delvdsevmax*CM3*delvsatevgt*sigma;
    c           = vgte*vdse;
    d           = 1+A2*c;
    e           = vdse*delvgtevgt;
    f           = A2*(*cgd);
    *cdrain    += A1*(d*(*cgd) - (*cgs));
    *gds       += A1*(d*(*gmd)+f*(vgte*dvdsevds+e*sigma));
    *gm        += A1*(d*(*gmg)+f*(vgte*dvdsevgs+e*delvgtvgs) - (*ggs));
  }

}


double diode(double u)
{

#define U0 (-2.303)
#define A (2.221)
#define B (6.804)
#define C (1.685)
  	double it;
  	double ut;
  	double b;
  	double c;
  	double i;
  	double expu=exp(u);
  	
  	if(u <= U0)
    {
    	it = expu*(1-expu);
  	}else                                             
    {
    	b = 0.5*(u-U0);
    	it = u + A*exp((U0-u)/B) - log(b+sqrt(b*b + 0.25*C*C));
    }
  	
  	ut = it + log(it);
  	b = u-ut;
  	c = 1+it;
  	i = it*(1 + b/c + 0.5*b*b/c/c/c);
  	return(i);
}