Datasheet

1
16
2
3
4
5
6
7
8
15
14
13
11
12
9
10
20
19
18
17
R
T
JA

=
165
o
C - 152
o
C
304 mW
= 42.8
o
C/W
LM26420
SNVS579F –FEBRUARY 2009–REVISED MARCH 2013 www.ti.com
P
INTERNAL
= 304mW (42)
(43)
If the junction temperature was to be kept below 125°C, then the ambient temperature could not go above
112°C.
T
j
- (R
θJA
x P
INTERNAL
) = T
A
(44)
125°C - (42.8°C/W x 304mW) = 112.0°C (45)
Layout Considerations
Figure 43. Internal Connection
For certain high power applications, the PCB land may be modified to a dog bone shape (see Figure 44). By
increasing the size of ground plane, and adding thermal vias, the R
θJA
for the application can be reduced.
Figure 44. PCB Dog Bone Layout
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