introduce geometry and frequency dependency for the flicker noise model

src/spicelib/devices/res/res.c

@@ -58,7 +58,10 @@ IFparm RESmPTable[] = { /* model parameters */
     IOPXU( "tnom",   RES_MOD_TNOM,     IF_REAL,"Parameter measurement temperature"),
     IOP(   "r",      RES_MOD_R,        IF_REAL,"Resistor model default value"),
     IOPR(  "res",    RES_MOD_R,        IF_REAL,"Resistor model default value"),
-    IOP(   "bv_max", RES_MOD_BV_MAX,   IF_REAL,"maximum voltage over resistor")
+    IOP(   "bv_max", RES_MOD_BV_MAX,   IF_REAL,"maximum voltage over resistor"),
+    IOP(   "lf",     RES_MOD_LF,       IF_REAL,"noise area length exponent"),
+    IOP(   "wf",     RES_MOD_WF,       IF_REAL,"noise area width exponent"),
+    IOP(   "ef",     RES_MOD_EF,       IF_REAL,"noise frequency exponent")
 };
 
 char *RESnames[] = {

src/spicelib/devices/res/resdefs.h

@@ -44,6 +44,7 @@ typedef struct sRESinstance {
     double REStc2;                  /* second temperature coefficient of resistors */
     double RESbv_max;               /* Maximum resistor voltage */
     int    RESnoisy;                /* Set if the resistor generates noise */
+    double RESeffNoiseArea;         /* effective resistor area for noise calculation */
     double *RESposPosptr;           /* pointer to sparse matrix diagonal at
                                      * (positive,positive) */
     double *RESnegNegptr;           /* pointer to sparse matrix diagonal at
@@ -110,6 +111,9 @@ typedef struct sRESmodel {       /* model structure for a resistor */
     double RESfNexp;        /* Flicker noise exponent */
     double RESres;          /* Default model resistance */
     double RESbv_max;       /* Maximum resistor voltage */
+    double RESlf;           /* length exponent for noise calculation */
+    double RESwf;           /* width exponent for noise calculation */
+    double RESef;           /* frequncy exponent for noise calculation */
     unsigned REStnomGiven       :1; /* flag to indicate nominal temp. was given */
     unsigned REStc1Given        :1; /* flag to indicate tc1 was specified */
     unsigned REStc2Given        :1; /* flag to indicate tc2 was specified */
@@ -122,6 +126,9 @@ typedef struct sRESmodel {       /* model structure for a resistor */
     unsigned RESfNexpGiven      :1; /* flag to indicate af given */
     unsigned RESresGiven        :1; /* flag to indicate model resistance given */
     unsigned RESbv_maxGiven     :1; /* flags indicates maximum voltage is given */
+    unsigned RESlfGiven         :1; /* flags indicates lf is given */
+    unsigned RESwfGiven         :1; /* flags indicates wf is given */
+    unsigned RESefGiven         :1; /* flags indicates ef is given */
 } RESmodel;
 
 /* device parameters */
@@ -158,6 +165,9 @@ typedef struct sRESmodel {       /* model structure for a resistor */
 #define RES_MOD_KF 110
 #define RES_MOD_AF 111
 #define RES_MOD_BV_MAX 112
+#define RES_MOD_LF 113
+#define RES_MOD_WF 114
+#define RES_MOD_EF 115
 
 /* device questions */
 #define RES_QUEST_SENS_REAL      201

src/spicelib/devices/res/resmask.c

@@ -66,6 +66,15 @@ RESmodAsk(CKTcircuit *ckt, GENmodel *inModel, int which, IFvalue *value)
         case RES_MOD_R:
             value->rValue = model->RESres;
             return(OK);
+        case RES_MOD_LF:
+            value->rValue = model->RESlf;
+            return(OK);
+        case RES_MOD_WF:
+            value->rValue = model->RESwf;
+            return(OK);
+        case RES_MOD_EF:
+            value->rValue = model->RESef;
+            return(OK);
         default:
             return(E_BADPARM);
     }

src/spicelib/devices/res/resmpar.c

@@ -62,6 +62,18 @@ RESmParam(int param, IFvalue *value, GENmodel *inModel)
         model->RESbv_max = value->rValue;
         model->RESbv_maxGiven = TRUE;
         break;
+    case RES_MOD_LF:
+        model->RESlf = value->rValue;
+        model->RESlfGiven = TRUE;
+        break;
+    case RES_MOD_WF:
+        model->RESwf = value->rValue;
+        model->RESwfGiven = TRUE;
+        break;
+    case RES_MOD_EF:
+        model->RESef = value->rValue;
+        model->RESefGiven = TRUE;
+        break;
     case RES_MOD_R:
         if ( value->rValue > 1e-03 ) {
             model->RESres = value->rValue;

src/spicelib/devices/res/resnoise.c

@@ -135,7 +135,7 @@ RESnoise (int mode, int operation, GENmodel *genmodel, CKTcircuit *ckt,
                        
                        noizDens[RESFLNOIZ] *= inst->RESm * model->RESfNcoef * exp(model->RESfNexp *
                                               log(MAX(fabs(inst->REScurrent),
-                                              N_MINLOG))) / data->freq;
+                                              N_MINLOG))) / (inst->RESeffNoiseArea*pow(data->freq,model->RESef));
                        lnNdens[RESFLNOIZ]   = log(MAX(noizDens[RESFLNOIZ],N_MINLOG));
 
                        noizDens[RESTOTNOIZ] = noizDens[RESTHNOIZ] + noizDens[RESFLNOIZ];

src/spicelib/devices/res/ressetup.c

@@ -36,6 +36,9 @@ RESsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit*ckt, int *state)
         if(!model->RESshortGiven) model->RESshort       = 0.0;
         if(!model->RESfNcoefGiven) model->RESfNcoef     = 0.0;
         if(!model->RESfNexpGiven) model->RESfNexp       = 1.0;
+        if(!model->RESlfGiven) model->RESlf             = 1.0;
+        if(!model->RESwfGiven) model->RESwf             = 1.0;
+        if(!model->RESefGiven) model->RESef             = 1.0;
 
         if(!model->RESbv_maxGiven)
             model->RESbv_max = 1e99;
@@ -67,6 +70,12 @@ RESsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit*ckt, int *state)
             if(!here->RESbv_maxGiven)
                 here->RESbv_max = model->RESbv_max;
 
+            if((here->RESwidthGiven)||(here->RESlengthGiven))
+                here->RESeffNoiseArea = pow((here->RESlength-model->RESshort),model->RESlf)
+                                       *pow((here->RESwidth-model->RESnarrow),model->RESwf);
+            else
+                here->RESeffNoiseArea = 1.0;
+
 /* macro to make elements with built in test for out of memory */
 #define TSTALLOC(ptr,first,second) \
 do { if((here->ptr = SMPmakeElt(matrix, here->first, here->second)) == NULL){\