LM1117T-5.0 National Semiconductor, LM1117T-5.0 Datasheet - Page 11

• Manufacturer Part Number: LM1117T-5.0
• Description: IC,VOLT REGULATOR,FIXED,+5V,BIPOLAR,SIP,3PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LM1117T-5.0

• Rohs Compliant: NO

APPLICATION NOTE
The next parameter which must be calculated is the maxi-
mum allowable temperature rise, T
where T
ture (125˚C), and T
perature which will be encountered in the application.
Using the calculated values for T
mum allowable value for the junction-to-ambient thermal re-
sistance (
If the maximum allowable value for
package or 92˚C/W for TO-252 package, no heatsink is
*Tab of device attached to topside copper
136˚C/W for SOT-223 package or
T
JA
R
Layout
(max)=T
= T
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
J
(max) is the maximum allowable junction tempera-
R
JA
(max)/P
) can be calculated:
J
(max)-T
D
A
(max) is the maximum ambient tem-
Top Side (in
A
(max)
0.0123
0.066
0.066
0.175
0.284
0.392
0.53
0.76
0.3
0.5
1
0
0
0
0
0
R
2
(max) and P
R
)*
Copper Area
(Continued)
(max):
79˚C/W for TO-220
JA
TABLE 1.
is found to be
Bottom Side (in
D
, the maxi-
0.066
0.175
0.284
0.392
0.2
0.4
0.6
0.8
0.5
0
0
0
0
0
0
1
JA
Different Heatsink Area
2
11
)
needed since the package alone will dissipate enough heat
to satisfy these requirements. If the calculated value for
falls below these limits, a heatsink is required.
As a design aid, Table 1 shows the value of the
223 and TO-252 for different heatsink area. The copper pat-
terns that we used to measure these
end of the Application Notes Section. Figure 7 and Figure 8
reflects the same test results as what are in the Table 1
Figure 9 and Figure 10 shows the maximum allowable power
dissipation vs. ambient temperature for the SOT-223 and
TO-252 device. Figures Figure 11 and Figure 12 shows the
maximum allowable power dissipation vs. copper area (in
for the SOT-223 and TO-252 devices. Please see AN1028
for power enhancement techniques to be used with SOT-223
and TO-252 packages.
(
JA
,˚C/W) SOT-223
136
123
115
125
84
75
69
66
98
89
82
79
93
83
75
70
Thermal Resistance
(
JA
JA
,˚C/W) TO-252
s are shown at the
103
87
60
54
52
47
84
70
63
57
57
89
72
61
55
53
www.national.com
JA
of SOT-
JA
2
)