add the mtriode parameter scale the triode region independently from saturation current

src/spicelib/devices/vdmos/vdmos.c

@@ -91,6 +91,7 @@ IFparm VDMOSmPTable[] = { /* model parameters */
  IOP("rd",    VDMOS_MOD_RD,    IF_REAL,   "Drain ohmic resistance"),
  IOP("rs",    VDMOS_MOD_RS,    IF_REAL,   "Source ohmic resistance"),
  IOP("rg",    VDMOS_MOD_RG,    IF_REAL,   "Gate ohmic resistance"),
+ IOP("mtriode", VDMOS_MOD_MTRIODE, IF_REAL,   "Conductance multiplier in triode region"),
 
 /* body diode */
  IOP("bv",    VDMOS_MOD_BV,    IF_REAL,   "Vds breakdown voltage"),

src/spicelib/devices/vdmos/vdmosdefs.h

@@ -326,6 +326,7 @@ typedef struct sVDMOSmodel {       /* model structure for a resistor */
     double VDMOScgdmax;
     double VDMOSa;
     double VDMOScgs;
+    double VDMOSmtr;
 
     /* bulk diode */
     double VDIOjunctionCap;   /* input - use tCj */
@@ -368,6 +369,7 @@ typedef struct sVDMOSmodel {       /* model structure for a resistor */
     unsigned VDMOScgdmaxGiven   :1;
     unsigned VDMOScgsGiven   :1;
     unsigned VDMOSaGiven   :1;
+    unsigned VDMOSmtrGiven   :1;
 
     unsigned VDMOSDbvGiven   :1;
     unsigned VDMOSDibvGiven   :1;
@@ -431,6 +433,7 @@ enum {
     VDMOS_MOD_A,
     VDMOS_MOD_CGS,
     VDMOS_MOD_RB,
+    VDMOS_MOD_MTRIODE,
     VDMOS_MOD_BV,
     VDMOS_MOD_IBV,
     VDMOS_MOD_NBV,

src/spicelib/devices/vdmos/vdmosload.c

@@ -403,8 +403,10 @@ VDMOSload(GENmodel *inModel, CKTcircuit *ckt)
                     /*
                      *     saturation region
                      */
+                    /* scale vds with mtr */
+                    double mtr = model->VDMOSmtr;
                     betap = Beta*(1 + model->VDMOSlambda*(vds*here->VDMOSmode));
-                    if (vgst <= (vds * here->VDMOSmode)) {
+                    if (vgst <= (vds * here->VDMOSmode) * mtr) {
                         cdrain = betap*vgst*vgst*.5;
                         here->VDMOSgm = betap*vgst;
                         here->VDMOSgds = model->VDMOSlambda*Beta*vgst*vgst*.5;
@@ -413,13 +415,13 @@ VDMOSload(GENmodel *inModel, CKTcircuit *ckt)
                         /*
                          *     linear region
                          */
-                        cdrain = betap * (vds * here->VDMOSmode) *
-                                 (vgst - .5 * (vds * here->VDMOSmode));
-                        here->VDMOSgm = betap * (vds * here->VDMOSmode);
-                        here->VDMOSgds = betap * (vgst - (vds * here->VDMOSmode)) +
+                        cdrain = betap * (vds * here->VDMOSmode) * mtr *
+                                 (vgst - .5 * (vds*here->VDMOSmode) * mtr);
+                        here->VDMOSgm = betap * (vds * here->VDMOSmode) * mtr;
+                        here->VDMOSgds = betap * (vgst - (vds * here->VDMOSmode) * mtr) +
                                          model->VDMOSlambda * Beta *
-                                         (vds * here->VDMOSmode) *
-                                         (vgst - .5 * (vds * here->VDMOSmode));
+                                         (vds * here->VDMOSmode) * mtr *
+                                         (vgst - .5 * (vds * here->VDMOSmode) * mtr);
                         here->VDMOSgmbs = here->VDMOSgm * arg;
                     }
                 }

src/spicelib/devices/vdmos/vdmosmask.c

@@ -45,6 +45,9 @@ VDMOSmAsk(CKTcircuit *ckt, GENmodel *inst, int which, IFvalue *value)
         case VDMOS_MOD_RG:
             value->rValue = model->VDMOSgateResistance;
             return(OK);
+        case VDMOS_MOD_MTRIODE:
+            value->rValue = model->VDMOSmtr;
+            return(OK);
         case VDMOS_MOD_TYPE:
             if (model->VDMOStype > 0)
                 value->sValue = "vdmosn";

src/spicelib/devices/vdmos/vdmosmpar.c

@@ -117,6 +117,10 @@ VDMOSmParam(int param, IFvalue *value, GENmodel *inModel)
             model->VDMOScgs = value->rValue;
             model->VDMOScgsGiven = TRUE;
             break;
+        case VDMOS_MOD_MTRIODE:
+            model->VDMOSmtr = value->rValue;
+            model->VDMOSmtrGiven = TRUE;
+            break;
         case VDMOS_MOD_BV:
             model->VDMOSDbv = value->rValue;
             model->VDMOSDbvGiven = TRUE;

src/spicelib/devices/vdmos/vdmosset.c

@@ -72,6 +72,9 @@ VDMOSsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit *ckt,
         if (!model->VDMOSaGiven) {
             model->VDMOSa = 1.;
         }
+        if (!model->VDMOSmtrGiven) {
+            model->VDMOSmtr = 1.;
+        }
         if (!model->VDMOSDbvGiven) {
             model->VDMOSDbv = 1.0e30;
         }