www.fairchildsemi.com
LM337
3-Terminal 1.5A Negative Adjustable Regulator
Features
•
•
•
•
•
•
•
Output Current in Excess of 1.5A
Output Voltage Adjustable Between -1.2V and -37V
Internal Thermal Overload Protection
Internal Short Circuit Current Limiting
Output Transistor Safe Area Compensation
Floating Operation for High Voltage Applications
Standard 3-Pin TO-220 Package
Description
The LM337 is a 3-terminal negative adjustable regulator. It
supplies in excess of 1.5A over an output voltage range of
-1.2V to -37V. This regulator requires only two external
resistor to set the output voltage. Included on the chip are
current limiting, thermal overload protection and safe area
compensation.
TO-220
1
1. Adj 2. Input 3. Output
Internal Block Diagram
Vadj
1
3
Output
Voltage
Reference
-
+
Protection
Circuitry
2
Input
Rev. 1.0.3
©2010 Fairchild Semiconductor Corporation
LM337
Absolute Maximum Ratings
Parameter
Input-Output Voltage Differential
Power Dissipation
Operating Temperature Range
Storage Temperature Range
Symbol
|V
I
- V
O
|
P
D
T
OPR
T
STG
Value
40
Internally limited
0 ~ +125
-65 ~ +125
Unit
V
W
°C
°C
Electrical Characteristics
(V
I
- V
O
= 5V, I
O
= 40mA, 0°C
≤
T
J
≤
+125°C, P
DMAX
= 20W, unless otherwise specified)
Parameter
Line Regulation (Note1)
Symbol
R
line
Conditions
T
A
= +25°C
3V
≤
I
V
I
- V
O
I
≤
40V
3V
≤
I V
I
- V
O
I
≤
40V
Load Regulation (Note1)
Adjustable Pin Current
Adjustable Pin Current Change
R
load
I
ADJ
ΔI
ADJ
T
A
= +25°C
10mA
≤
I
O
≤
0.5A
10mA
≤
I
O
≤
1.5A
-
T
A
= +25°C
10mA
≤
I
O
≤
1.5A
3V
≤I
V
I
- V
O
I
≤
40V
T
A
= +25°C
Reference Voltage
Temperature Stability
Minimum Load Current to Maintain
Regulation
RMS Noise, % of V
OUT
Ripple Rejection Ratio
Long Term Stability
Thermal Resistance Junction to
Case
Note:
Min.
-
-
-
-
-
-
Typ.
0.01
0.02
15
15
50
2
Max.
0.04
0.07
50
150
100
5
Unit
%/ V
mV
μA
μA
-1.213 -1.250 -1.287
-1.200 -1.250 -1.300
-
-
-
-
-
66
-
-
0.6
2.5
1.5
0.003
60
77
0.3
4
-
10
6
-
-
-
1
-
V
%
mA
%
dB
%
°C/W
V
REF
ST
T
I
L(MIN)
e
N
RR
ST
R
θJC
3V
≤
I V
I
- V
O
I
≤
40V
10mA
≤
I
O
≤
1.5A
0°C
≤ ΤJ ≤ +125°C
3V
≤I
V
I
- V
O
I
≤
40V
3V
≤I
V
I
- V
O
I
≤
10V
T
A
= +25°C 10Hz
≤
f
≤10kHz
V
O
= -10V, f = 120Hz
C
ADJ
= 10μF (Note2)
T
J
= 125°C ,1000Hours
-
1. Load and line regulation are specified at constant junction temperature. Change in V
O
due to heating effects must
be taken into account separately. Pulse testing with low duty is used.
2. C
ADJ
, when used, is connected between the adjustment pin and ground.
2
LM337
Typical Application
I
PROG
R
2
Ci
0. 1
μ
F
+
I
adj
Vadj
+
R
1
Vo
Co
1
μ
F
-V
I
VI
KA337
LM337
-V
o
Figure 1. Programmable Regulator
• Ci is required if regulator is located more then 4 inches from power supply filter.
A 1.0μF solid tantalum or 10μF aluminum electrolytic is recommended.
Co is necessary for stability. A 1.0μF solid tantalum or 10μF aluminum electrolytic is recommended.
• V
O
= -1.25V (1+R
2
/R
1
)
3
LM337
Mechanical Dimensions
Package
Dimensions in millimeters
TO-220 [SINGLE GAUGE]
4
LM337
Ordering Information
Product Number
LM337T
Package
TO-220
Operating Temperature
0°C to +125°C
5
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