diff --git a/src/spicelib/devices/bsim4/b4.c b/src/spicelib/devices/bsim4/b4.c
index 438c1498b..83f3115e5 100644
--- a/src/spicelib/devices/bsim4/b4.c
+++ b/src/spicelib/devices/bsim4/b4.c
@@ -59,6 +59,7 @@ IOP( "mulu0", BSIM4_MULU0, IF_REAL, "Low field mobility multiplier"),
 IOP( "xgw",  BSIM4_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4_NGCON, IF_REAL, "Number of gate contacts"),
 IOP( "wnflag", BSIM4_WNFLAG, IF_INTEGER, "W/NF device flag for bin selection"),
+IOPU("dtemp", BSIM4_DTEMP, IF_REAL,    "Instance temperature difference"),
 
 IOP( "trnqsmod", BSIM4_TRNQSMOD, IF_INTEGER, "Transient NQS model selector"),
 IOP( "acnqsmod", BSIM4_ACNQSMOD, IF_INTEGER, "AC NQS model selector"),
diff --git a/src/spicelib/devices/bsim4/b4ask.c b/src/spicelib/devices/bsim4/b4ask.c
index d43e1a708..abced660c 100644
--- a/src/spicelib/devices/bsim4/b4ask.c
+++ b/src/spicelib/devices/bsim4/b4ask.c
@@ -135,6 +135,9 @@ BSIM4instance *here = (BSIM4instance*)inst;
         case BSIM4_WNFLAG:
             value->iValue = here->BSIM4wnflag;
             return(OK);
+        case BSIM4_DTEMP:
+            value->rValue = here->BSIM4dtemp;
+            return(OK);
         case BSIM4_XGW:
             value->rValue = here->BSIM4xgw;
             return(OK);
diff --git a/src/spicelib/devices/bsim4/b4par.c b/src/spicelib/devices/bsim4/b4par.c
index ac4a274c5..44373bfd6 100644
--- a/src/spicelib/devices/bsim4/b4par.c
+++ b/src/spicelib/devices/bsim4/b4par.c
@@ -165,6 +165,10 @@ IFvalue *select)
             here->BSIM4wnflag = value->iValue;
             here->BSIM4wnflagGiven = TRUE;
             break;
+        case BSIM4_DTEMP:
+            here->BSIM4dtemp = value->rValue;
+            here->BSIM4dtempGiven = TRUE;
+            return(OK);
         case BSIM4_XGW:
             here->BSIM4xgw = value->rValue;
             here->BSIM4xgwGiven = TRUE;
diff --git a/src/spicelib/devices/bsim4/b4set.c b/src/spicelib/devices/bsim4/b4set.c
index 71bc75a81..0e91f37d3 100644
--- a/src/spicelib/devices/bsim4/b4set.c
+++ b/src/spicelib/devices/bsim4/b4set.c
@@ -2371,6 +2371,8 @@ BSIM4instance **InstArray;
                 here->BSIM4xgw = model->BSIM4xgw;
             if (!here->BSIM4ngconGiven)
                 here->BSIM4ngcon = model->BSIM4ngcon;
+            if (!here->BSIM4dtempGiven)
+                here->BSIM4dtemp = 0;
 
             /* Process instance model selectors, some
              * may override their global counterparts
diff --git a/src/spicelib/devices/bsim4/bsim4def.h b/src/spicelib/devices/bsim4/bsim4def.h
index 6d7d652e8..17f810a19 100644
--- a/src/spicelib/devices/bsim4/bsim4def.h
+++ b/src/spicelib/devices/bsim4/bsim4def.h
@@ -121,6 +121,7 @@ typedef struct sBSIM4instance
     int BSIM4wnflag;
     double BSIM4xgw;
     double BSIM4ngcon;
+    double BSIM4dtemp;
 
     /* added here to account stress effect instance dependence */
 
@@ -316,6 +317,7 @@ typedef struct sBSIM4instance
     unsigned BSIM4wnflagGiven   :1;
     unsigned BSIM4xgwGiven   :1;
     unsigned BSIM4ngconGiven   :1;
+    unsigned BSIM4dtempGiven : 1;
     unsigned BSIM4icVDSGiven :1;
     unsigned BSIM4icVGSGiven :1;
     unsigned BSIM4icVBSGiven :1;
@@ -2884,6 +2886,8 @@ typedef struct sBSIM4model
 #define BSIM4_WEFF                46
 #define BSIM4_LEFF                47
 
+#define BSIM4_DTEMP               48
+
 /* Global parameters */
 #define BSIM4_MOD_TEMPEOT         66
 #define BSIM4_MOD_LEFFEOT         67