diff --git a/src/spicelib/devices/bsim4v5/b4v5.c b/src/spicelib/devices/bsim4v5/b4v5.c
index 2d920af47..30d05ac74 100644
--- a/src/spicelib/devices/bsim4v5/b4v5.c
+++ b/src/spicelib/devices/bsim4v5/b4v5.c
@@ -49,7 +49,7 @@ IOPR( "delvt0", BSIM4v5_DELVTO,  IF_REAL   , "Zero bias threshold voltage variat
 IOP( "mulu0", BSIM4v5_MULU0, IF_REAL, "Low field mobility multiplier"),
 IOP( "xgw",  BSIM4v5_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4v5_NGCON, IF_REAL, "Number of gate contacts"),
-
+IOPU("dtemp", BSIM4v5_DTEMP, IF_REAL,    "Instance temperature difference"),
 
 IOP( "trnqsmod", BSIM4v5_TRNQSMOD, IF_INTEGER, "Transient NQS model selector"),
 IOP( "acnqsmod", BSIM4v5_ACNQSMOD, IF_INTEGER, "AC NQS model selector"),
diff --git a/src/spicelib/devices/bsim4v5/b4v5ask.c b/src/spicelib/devices/bsim4v5/b4v5ask.c
index 95ae3c800..829bb3e4c 100644
--- a/src/spicelib/devices/bsim4v5/b4v5ask.c
+++ b/src/spicelib/devices/bsim4v5/b4v5ask.c
@@ -112,6 +112,9 @@ BSIM4v5instance *here = (BSIM4v5instance*)inst;
         case BSIM4v5_MULU0:
             value->rValue = here->BSIM4v5mulu0;
             return(OK);
+        case BSIM4v5_DTEMP:
+            value->rValue = here->BSIM4v5dtemp;
+            return(OK);
         case BSIM4v5_XGW:
             value->rValue = here->BSIM4v5xgw;
             return(OK);
diff --git a/src/spicelib/devices/bsim4v5/b4v5par.c b/src/spicelib/devices/bsim4v5/b4v5par.c
index 1013ce700..f3c07dee7 100644
--- a/src/spicelib/devices/bsim4v5/b4v5par.c
+++ b/src/spicelib/devices/bsim4v5/b4v5par.c
@@ -139,6 +139,10 @@ IFvalue *select)
             here->BSIM4v5mulu0 = value->rValue;
             here->BSIM4v5mulu0Given = TRUE;
             break;
+        case BSIM4v5_DTEMP:
+            here->BSIM4v5dtemp = value->rValue;
+            here->BSIM4v5dtempGiven = TRUE;
+            return(OK);
         case BSIM4v5_XGW:
             here->BSIM4v5xgw = value->rValue;
             here->BSIM4v5xgwGiven = TRUE;
diff --git a/src/spicelib/devices/bsim4v5/b4v5set.c b/src/spicelib/devices/bsim4v5/b4v5set.c
index d16f3747b..9214bc3ca 100644
--- a/src/spicelib/devices/bsim4v5/b4v5set.c
+++ b/src/spicelib/devices/bsim4v5/b4v5set.c
@@ -1751,8 +1751,9 @@ BSIM4v5instance **InstArray;
                 here->BSIM4v5xgw = model->BSIM4v5xgw;
             if (!here->BSIM4v5ngconGiven)
                 here->BSIM4v5ngcon = model->BSIM4v5ngcon;
+            if (!here->BSIM4v5dtempGiven)
+                here->BSIM4v5dtemp = 0;
 
-                    
             /* Process instance model selectors, some
              * may override their global counterparts
 	     */
diff --git a/src/spicelib/devices/bsim4v5/bsim4v5def.h b/src/spicelib/devices/bsim4v5/bsim4v5def.h
index 2120a59d3..f397af3b7 100644
--- a/src/spicelib/devices/bsim4v5/bsim4v5def.h
+++ b/src/spicelib/devices/bsim4v5/bsim4v5def.h
@@ -105,6 +105,7 @@ typedef struct sBSIM4v5instance
     double BSIM4v5mulu0;
     double BSIM4v5xgw;
     double BSIM4v5ngcon;
+    double BSIM4v5dtemp;
 
      /* added here to account stress effect instance dependence */
     double BSIM4v5u0temp;
@@ -288,6 +289,7 @@ typedef struct sBSIM4v5instance
     unsigned BSIM4v5mulu0Given   :1;
     unsigned BSIM4v5xgwGiven   :1;
     unsigned BSIM4v5ngconGiven   :1;
+    unsigned BSIM4v5dtempGiven : 1;
     unsigned BSIM4v5icVDSGiven :1;
     unsigned BSIM4v5icVGSGiven :1;
     unsigned BSIM4v5icVBSGiven :1;
@@ -2536,6 +2538,7 @@ typedef struct sBSIM4v5model
 #define BSIM4v5_SC                  37
 #define BSIM4v5_M                   38
 #define BSIM4v5_MULU0               39
+#define BSIM4v5_DTEMP               40
 
 /* Global parameters */
 #define BSIM4v5_MOD_TEMPMOD         89