lateral diffusion and overlap capacitance removed

src/spicelib/devices/vdmos/vdmos.c

@@ -132,7 +132,6 @@ IFparm VDMOSmPTable[] = { /* model parameters */
  IOP("mjsw",  VDMOS_MOD_MJSW,  IF_REAL,   "Side grading coefficient"),
  IOP("js",    VDMOS_MOD_JS,    IF_REAL,   "Bulk jct. sat. current density"),
  IOP("tox",   VDMOS_MOD_TOX,   IF_REAL,   "Oxide thickness"),
- IOP("ld",    VDMOS_MOD_LD,    IF_REAL,   "Lateral diffusion"),
  IOP("u0",    VDMOS_MOD_U0,    IF_REAL,   "Surface mobility"),
  IOPR("uo",   VDMOS_MOD_U0,    IF_REAL,   "Surface mobility"),
  IOP("fc",    VDMOS_MOD_FC,    IF_REAL,   "Forward bias jct. fit parm."),

src/spicelib/devices/vdmos/vdmosdefs.h

@@ -300,7 +300,6 @@ typedef struct sVDMOSmodel {       /* model structure for a resistor */
 
     int VDMOStype;       /* device type : 1 = nmos,  -1 = pmos */
     double VDMOStnom;        /* temperature at which parameters measured */
-    double VDMOSlatDiff;
     double VDMOSjctSatCurDensity;    /* input - use tSatCurDens */
     double VDMOSjctSatCur;   /* input - use tSatCur */
     double VDMOSdrainResistance;
@@ -334,7 +333,6 @@ typedef struct sVDMOSmodel {       /* model structure for a resistor */
     double VDMOScgs;
 
     unsigned VDMOStypeGiven  :1;
-    unsigned VDMOSlatDiffGiven   :1;
     unsigned VDMOSjctSatCurDensityGiven  :1;
     unsigned VDMOSjctSatCurGiven :1;
     unsigned VDMOSdrainResistanceGiven   :1;
@@ -419,7 +417,6 @@ enum {
     VDMOS_MOD_MJSW,
     VDMOS_MOD_JS,
     VDMOS_MOD_TOX,
-    VDMOS_MOD_LD,
     VDMOS_MOD_RSH,
     VDMOS_MOD_U0,
     VDMOS_MOD_FC,

src/spicelib/devices/vdmos/vdmosdset.c

@@ -22,8 +22,6 @@ VDMOSdSetup(GENmodel *inModel, CKTcircuit *ckt)
     VDMOSinstance *here;
     double Beta;
     double DrainSatCur;
-    double EffectiveLength;
-    double OxideCap;
     double SourceSatCur;
     double gm;
     double gds;
@@ -83,7 +81,6 @@ VDMOSdSetup(GENmodel *inModel, CKTcircuit *ckt)
                 here=VDMOSnextInstance(here)) {
 
             vt = CONSTKoverQ * here->VDMOStemp;
-            EffectiveLength=here->VDMOSl - 2*model->VDMOSlatDiff;
 
              if( (here->VDMOStSatCurDens == 0) ||
                     (here->VDMOSdrainArea == 0) ||
@@ -97,9 +94,7 @@ VDMOSdSetup(GENmodel *inModel, CKTcircuit *ckt)
                         here->VDMOSm * here->VDMOSsourceArea;
             }
             Beta = here->VDMOStTransconductance * here->VDMOSm *
-                    here->VDMOSw/EffectiveLength;
-            OxideCap = model->VDMOSoxideCapFactor * EffectiveLength * 
-                    here->VDMOSm * here->VDMOSw;
+                    here->VDMOSw/here->VDMOSl;
 
                     vbs = model->VDMOStype * ( 
                         *(ckt->CKTrhsOld+here->VDMOSbNode) -
@@ -440,7 +435,7 @@ VDMOSdSetup(GENmodel *inModel, CKTcircuit *ckt)
 
 
     phi = here->VDMOStPhi;
-    cox = OxideCap;
+    cox = 0;/*FIXME: can we do disto without knowing the oxide thickness?*/
     if (vgst <= -phi) {
     lcapgb2=lcapgb3=lcapgs2=lcapgs3=lcapgd2=lcapgd3=0;
     } else if (vgst <= -phi/2) {

src/spicelib/devices/vdmos/vdmosmask.c

@@ -96,9 +96,6 @@ VDMOSmAsk(CKTcircuit *ckt, GENmodel *inst, int which, IFvalue *value)
         case VDMOS_MOD_TOX:
             value->rValue = model->VDMOSoxideThickness;
             return(OK);
-        case VDMOS_MOD_LD:
-            value->rValue = model->VDMOSlatDiff;
-            return(OK);
         case VDMOS_MOD_RSH:
             value->rValue = model->VDMOSsheetResistance;
             return(OK);

src/spicelib/devices/vdmos/vdmosmpar.c

@@ -91,10 +91,6 @@ VDMOSmParam(int param, IFvalue *value, GENmodel *inModel)
             model->VDMOSoxideThickness = value->rValue;
             model->VDMOSoxideThicknessGiven = TRUE;
             break;
-        case VDMOS_MOD_LD:
-            model->VDMOSlatDiff = value->rValue;
-            model->VDMOSlatDiffGiven = TRUE;
-            break;
         case VDMOS_MOD_RSH:
             model->VDMOSsheetResistance = value->rValue;
             model->VDMOSsheetResistanceGiven = TRUE;

src/spicelib/devices/vdmos/vdmosnoi.c

@@ -110,7 +110,7 @@ VDMOSnoise (int mode, int operation, GENmodel *genmodel, CKTcircuit *ckt,
 				 log(MAX(fabs(inst->VDMOScd),N_MINLOG))) /
 				 (data->freq * inst->VDMOSw * 
 				 inst->VDMOSm *
-				 (inst->VDMOSl - 2*model->VDMOSlatDiff) * coxSquared);
+				 inst->VDMOSl * coxSquared);
 		    lnNdens[VDMOSFLNOIZ] = 
 				 log(MAX(noizDens[VDMOSFLNOIZ],N_MINLOG));
 

src/spicelib/devices/vdmos/vdmosset.c

@@ -30,9 +30,6 @@ VDMOSsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit *ckt,
         if (!model->VDMOStypeGiven) {
             model->VDMOStype = NMOS;
         }
-        if (!model->VDMOSlatDiffGiven) {
-            model->VDMOSlatDiff = 0;
-        }
         if (!model->VDMOSjctSatCurDensityGiven) {
             model->VDMOSjctSatCurDensity = 0;
         }

src/spicelib/devices/vdmos/vdmostemp.c

@@ -157,11 +157,6 @@ VDMOStemp(GENmodel *inModel, CKTcircuit *ckt)
                 here->VDMOSw = 1;
             }
 
-            if(here->VDMOSl - 2 * model->VDMOSlatDiff <=0) {
-                SPfrontEnd->IFerrorf (ERR_WARNING,
-                        "%s: effective channel length less than zero",
-                        model->VDMOSmodName);
-            }
             ratio4 = ratio * sqrt(ratio);
             here->VDMOStTransconductance = model->VDMOStransconductance / ratio4;
             here->VDMOStSurfMob = model->VDMOSsurfaceMobility/ratio4;