diff --git a/src/spicelib/devices/bjt/bjt.c b/src/spicelib/devices/bjt/bjt.c
index 9c8c64d7c..7c0fb832f 100644
--- a/src/spicelib/devices/bjt/bjt.c
+++ b/src/spicelib/devices/bjt/bjt.c
@@ -221,6 +221,8 @@ IFparm BJTmPTable[] = { /* model parameters */
  IOP("tise2", BJT_MOD_TISE2, IF_REAL, "ISE 2. temperature coefficient"),
  IOP("tisc1", BJT_MOD_TISC1, IF_REAL, "ISC 1. temperature coefficient"),
  IOP("tisc2", BJT_MOD_TISC2, IF_REAL, "ISC 2. temperature coefficient"),
+ IOP("tiss1", BJT_MOD_TISS1, IF_REAL, "ISS 1. temperature coefficient"),
+ IOP("tiss2", BJT_MOD_TISS2, IF_REAL, "ISS 2. temperature coefficient"),
  IOP("quasimod", BJT_MOD_QUASIMOD, IF_INTEGER, "Temperature equation selector"),
  IOP("vg",   BJT_MOD_EGQS,   IF_REAL, "Energy gap for QS temp. dependency"),
  IOP("cn",    BJT_MOD_XRCI,  IF_REAL, "Temperature exponent of RCI"),
diff --git a/src/spicelib/devices/bjt/bjtdefs.h b/src/spicelib/devices/bjt/bjtdefs.h
index 625db4772..9064f7a8c 100644
--- a/src/spicelib/devices/bjt/bjtdefs.h
+++ b/src/spicelib/devices/bjt/bjtdefs.h
@@ -489,6 +489,8 @@ typedef struct sBJTmodel {          /* model structure for a bjt */
     double BJTtise2;
     double BJTtisc1;
     double BJTtisc2;
+    double BJTtiss1;
+    double BJTtiss2;
     int    BJTquasimod;
     double BJTenergyGapQS;
     double BJTtempExpRCI;
@@ -606,6 +608,8 @@ typedef struct sBJTmodel {          /* model structure for a bjt */
     unsigned BJTtise2Given : 1;
     unsigned BJTtisc1Given : 1;
     unsigned BJTtisc2Given : 1;
+    unsigned BJTtiss1Given : 1;
+    unsigned BJTtiss2Given : 1;
     unsigned BJTquasimodGiven : 1;
     unsigned BJTenergyGapQSGiven : 1;
     unsigned BJTtempExpRCIGiven : 1;
@@ -757,6 +761,8 @@ enum {
     BJT_MOD_TISE2,
     BJT_MOD_TISC1,
     BJT_MOD_TISC2,
+    BJT_MOD_TISS1,
+    BJT_MOD_TISS2,
     BJT_MOD_QUASIMOD,
     BJT_MOD_EGQS,
     BJT_MOD_XRCI,
diff --git a/src/spicelib/devices/bjt/bjtmask.c b/src/spicelib/devices/bjt/bjtmask.c
index 2034b1826..b68464d02 100644
--- a/src/spicelib/devices/bjt/bjtmask.c
+++ b/src/spicelib/devices/bjt/bjtmask.c
@@ -390,6 +390,12 @@ BJTmAsk(CKTcircuit *ckt, GENmodel *instPtr, int which, IFvalue *value)
         case BJT_MOD_TISC2:
             value->rValue = here->BJTtisc2;
             return(OK);
+        case BJT_MOD_TISS1:
+            value->rValue = here->BJTtiss1;
+            return(OK);
+        case BJT_MOD_TISS2:
+            value->rValue = here->BJTtiss2;
+            return(OK);
         case BJT_MOD_QUASIMOD:
             value->iValue = here->BJTquasimod;
             return(OK);
diff --git a/src/spicelib/devices/bjt/bjtmpar.c b/src/spicelib/devices/bjt/bjtmpar.c
index 51409905b..63a369bb6 100644
--- a/src/spicelib/devices/bjt/bjtmpar.c
+++ b/src/spicelib/devices/bjt/bjtmpar.c
@@ -470,6 +470,14 @@ BJTmParam(int param, IFvalue *value, GENmodel *inModel)
             mods->BJTtisc2 = value->rValue;
             mods->BJTtisc2Given = TRUE;
             break;
+        case BJT_MOD_TISS1:
+            mods->BJTtiss1 = value->rValue;
+            mods->BJTtiss1Given = TRUE;
+            break;
+        case BJT_MOD_TISS2:
+            mods->BJTtiss2 = value->rValue;
+            mods->BJTtiss2Given = TRUE;
+            break;
         case BJT_MOD_QUASIMOD:
             mods->BJTquasimod = value->iValue;
             mods->BJTquasimodGiven = TRUE;
diff --git a/src/spicelib/devices/bjt/bjtsetup.c b/src/spicelib/devices/bjt/bjtsetup.c
index d7c5bbe05..9b8d900cb 100644
--- a/src/spicelib/devices/bjt/bjtsetup.c
+++ b/src/spicelib/devices/bjt/bjtsetup.c
@@ -335,6 +335,12 @@ BJTsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit *ckt, int *states)
         if(!model->BJTtisc2Given) {
             model->BJTtisc2 = 0.0;
         }
+        if(!model->BJTtiss1Given) {
+            model->BJTtiss1 = 0.0;
+        }
+        if(!model->BJTtiss2Given) {
+            model->BJTtiss2 = 0.0;
+        }
         if(!model->BJTquasimodGiven) {
             model->BJTquasimod = 0;
         }
diff --git a/src/spicelib/devices/bjt/bjttemp.c b/src/spicelib/devices/bjt/bjttemp.c
index eb80b50b5..be4dfa7aa 100644
--- a/src/spicelib/devices/bjt/bjttemp.c
+++ b/src/spicelib/devices/bjt/bjttemp.c
@@ -175,6 +175,7 @@ BJTtemp(GENmodel *inModel, CKTcircuit *ckt)
               here->BJTtSubSatCur = model->BJTsubSatCur * factor;
             } else if (model->BJTtlev == 3) {
               here->BJTtSatCur = pow(model->BJTsatCur,(1+model->BJTtis1*dt+model->BJTtis2*dt*dt));
+              here->BJTtSubSatCur = pow(model->BJTsubSatCur,(1+model->BJTtiss1*dt+model->BJTtiss2*dt*dt));
             }
 
             if (model->BJTintCollResistGiven) {
@@ -273,8 +274,12 @@ BJTtemp(GENmodel *inModel, CKTcircuit *ckt)
                     (1 - here->BJTtjunctionExpBC);
             here->BJTtVcrit = vt *
                      log(vt / (CONSTroot2*here->BJTtSatCur*here->BJTarea));
-            here->BJTtSubVcrit = vt *
-                     log(vt / (CONSTroot2*here->BJTtSubSatCur*here->BJTarea));
+            if(model->BJTsubSatCurGiven) {
+                here->BJTtSubVcrit = vt *
+                         log(vt / (CONSTroot2*here->BJTtSubSatCur*here->BJTarea));
+            } else {
+                here->BJTtSubVcrit = here->BJTtVcrit;
+            }
             here->BJTtf2 = exp((1 + here->BJTtjunctionExpBE) * xfc);
             here->BJTtf3 = 1 - model->BJTdepletionCapCoeff *
                     (1 + here->BJTtjunctionExpBE);