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LM317 3-Terminal Positive Adjustable Regulator
www.fairchildsemi.com
LM317
3-Terminal Positive Adjustable Regulator
Features
• Output Current In Excess of 1. 5A
• Output Adjustable Between 1. 2V and 37V
• Internal Thermal Overload Protection
• Internal Short Circuit Current Limiting
• Output Transistor Safe Operating Area Compensation
• TO-220 Package
Description
This monolithic integrated circuit is an adjustable 3-terminal
positive voltage regulator designed to supply more than 1.5A
of load current with an output voltage adjustable over a 1.2
to 37V. It employs internal current limiting, thermal
shut-down and safe area compensa tion.
TO-220
1
1. Adj 2. Output 3. Input
Internal Block Diagram
Input
3
+
-
Voltage
Reference
Protection
Circuitry
Rlimit
2
Vo
Output
1
Adj
Rev. 1.0.0
©2001 Fairchild Semiconductor Corporation
Vin
Vadj
11035330.005.png 11035330.006.png 11035330.007.png
LM317
Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
Input-Output Voltage Differential
V I - V O
40
V
Lead Temperature
T LEAD
230
C
Power Dissipation
P D
Internally limited
W
Operating Junction Temperature Range
T j
0 ~ +125
C
Storage Temperature Range
T STG
-65 ~+125
C
Temperature Coefficient of Output Voltage
Vo/
T
±0.02
%/
C
Electrical Characteristics
(V I -V O =5V, I O = 0.5A, 0
C
T J
+ 125
C, I MAX = 1.5A,
P DMAX = 20W, unless otherwise specified)
Parameter
Symbol
Conditions
Min Typ. Max.
Unit
T A = +25
C
-
0.01 0.04
% / V
Line Regulation (Note1)
Rline
3V
V I - V O
40V
3V
V I - V O
40V
-
0.02 0.07
% / V
T A = +25
C, 10mA
I O
I MAX
V O < 5V
V O
-
18
0.4
25
0.5
mV% / V O
5V
Load Regulation (Note1)
Rload
10mA
I O
I MAX
VO < 5V
V O
-
40
0.8
70
1.5
mV% / VO
5V
Adjustable Pin Current
I ADJ
-
-
46
100
A
Adjustable Pin Current Change
I ADJ
3V
V I - V O
40V
-
2.0
5
A
10mA
I O
I MAX P D
P MAX
3V
V IN - V O
40V
Reference Voltage
V REF
10mA
I O
I MAX
1.20 1.25 1.30
V
P D
P MAX
Temperature Stability
ST T
-
-
0.7
-
% / V O
Minimum Load Current to Maintain
Regulation
I L(MIN) V I - V O = 40V
-
3.5
12
mA
V I - V O
15V, P D
P MAX
2.2
0.3
Maximum Output Current
I O(MAX)
V I - V O
40V, P D
P MAX
1.0
-
A
TA=25
C
RMS Noise, % of V OUT
e N
T A = +25
C, 10Hz
f
10KHz
-
0.003 0.01
% / V O
Ripple Rejection
RR
V O = 10V, f = 120Hz
without C ADJ
C ADJ = 10
66
60
75
-
dB
F (Note2)
Long-Term Stability, T J = T HIGH
ST
C for end point
measurements, 1000HR
-
0.3
1
%
Thermal Resistance Junction to
Case
R
JC
-
-
5
-
C / W
Note:
1. Load and line regulation are specified at constant junction temperature. Change in V D due to heating effects must be taken
into account separately. Pulse testing with low duty is used. (P MAX = 20W)
2. C ADJ , when used, is connected between the adjustment pin and ground.
2
T A = +25
11035330.008.png
LM317
Typical Perfomance Characteristics
TEMPERATURE (
C)
TEMPERATURE (
C)
Figure 1. Load Regulation
Figure 2. Adjustment Current
TEMPERATURE (
C)
TEMPERATURE (
C)
Figure 3. Dropout Voltage
Figure 4. Reference Voltage
3
11035330.001.png
LM317
Typical Application
V I
VI
KA317
Vo
Output
Input
Vadj
Ci
0. 1
R 1
Co
1
F
I adj
F
R 2
I adj
V O = 1.25V (1+ R 2 / R 1 )+I adj R 2
Figure 5. Programmable Regulator
C i is required when regulator is located an appreciable distance from power supply filter.
C o is not needed for stability, however, it does improve transient response.
Since I ADJ is controlled to less than 100
A, the error associated with this term is negligible in most applications.
4
LM317
11035330.002.png 11035330.003.png
LM317
Mechanical Dimensions
Package
TO-220
9.90 ±
0.20
4.50 ±
0.20
(8.70)
ø3.60 ±
0.10
1.30 +0.10
–0.05
1.27 ±
0.10
1.52 ±
0.10
0.80 ±
0.10
0.50 +0.10
2.40 ±
–0.05
0.20
2.54TYP
[2.54 ±
2.54TYP
[2.54 ±
0.20 ]
0.20 ]
10.00 ±
0.20
5
11035330.004.png

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