LM117, LM317-N
SNVS774L –MAY 2004–REVISED FEBRUARY 2011
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Table 1. θJA Different Heatsink Area
Layout
Copper Area
Thermal Resistance
Top Side (in2)(1)
0.0123
Bottom Side (in2)
(θJA°C/W) PFM
1
2
0
0
103
87
60
54
52
47
84
70
63
57
57
89
72
61
55
53
0.066
0.3
3
0
4
0.53
0
5
0.76
0
6
1.0
0
7
0.066
0.066
0.066
0.066
0.066
0.066
0.175
0.284
0.392
0.5
0.2
0.4
0.6
0.8
1.0
0.066
0.175
0.284
0.392
0.5
8
9
10
11
12
13
14
15
16
(1) Tab of device attached to topside of copper.
Figure 33. θJA vs 2oz Copper Area for PFM
Figure 34. Maximum Allowable Power Dissipation vs. Ambient Temperature for PFM
14
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