
82 Heat Transfer: Thermal Management of Electronics
From Example 5-5,
and
The conduction thermal resistances of the die attach, the
substrate, and the convection thermal resistance on the bottom side of the sub-
strate are
R
L
kA
da
da
m
W/m°Cm
=
=
×
=
0 0001
20025
008
22
.
.
.
°°C/W
m
W/m°C
sub
sub
,
.
..
R
L
kA
=
=
×
0 0012
02 00
225
96
11
20 0 025
22
2
2
m
°C/W
W/mC
conv,2
2
=
==
×
.,
.
R
hA
mm
°C/W
2
80= .
Total thermal resistance form the active side of the die to ambient is
11 1
RRRRRR
die-ambientdie TIM cap conv,1 da
=
+++
+
+
RRR
R
subconv,2
die-ambient
+
=
++
11
0 013 0 032 00... 008 064
1
0089680
0 688
+
+
++
=
...
.R
die-ambi