1/13
March 2003
s
OUTPUT VOLTAGE ADJUSTABLE DOWN
TO V
ref
s
1.5A GUARANTEED OUTPUT CURRENT
s
0.3%/V TYPICAL LOAD REGULATION
s
0.01%/V TYPICAL LINE REGULATION
s
CURRENT LIMIT CONSTANT WITH
TEMPERATURE
s
RIPPLE REJECTION: 77dB
s
STANDARD 3-LEAD TRANSISTOR
PACKAGES
s
EXCELLENT THERMAL REGULATION:
0.002%/V
s
50ppm/C TEMPERATURE COEFFICIENT
DESCRIPTION
The LM137 series are adjustable 3-terminal
negative voltage regulators capable of supplying
in excess -1.5A over a -1.2 to -37V output voltage
range.
They are exceptionally easy to use and require
only two external resistors to set the output
voltage. Further, both line and load regulation are
better than standard fixed regulators. Also, LM137
regulators are supplied in standard transistor
packages which are easily mounted and handled.
In addition to higher performance than fixed
regulators, the LM137 series offer full overload
protection available only in integrated circuits.
Included on the chip are current limit, thermal
overload protection and safe area protection. All
overload
protection
circuitry
remains
fully
functional even if the adjustment terminal is
disconnected.
LM137/LM237
LM337
THREE-TERMINAL ADJUSTABLE
NEGATIVE VOLTAGE REGULATORS
SCHEMATIC DIAGRAM
TO-220
TO-3
LM137-LM237-LM337
2/13
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
THERMAL DATA
CONNECTION DIAGRAM (top view)
ORDERING CODES
Symbol
Parameter
Value
Unit
V
I
- V
O
Input Output Voltage Differential
40
V
I
O
Output Current
1.5
A
P
tot
Power Dissipation
Internally Limited
T
stg
Storage Temperature Range
-65 to 150
C
T
oper
Operating Junction Temperature Range
LM137
-55 to 150
C
LM237
-25 to 125
LM337
0 to 125
Symbol
Parameter
TO-220
TO-3
Unit
R
thj-case
Thermal Resistance Junction-case
Max
3
4
C/W
R
thj-amb
Thermal Resistance Junction-ambient
Max
70
35
C/W
TYPE
TO-3
TO-220
TEMPERATURE RANGE
LM137
LM137K
-55C to 150C
LM237
LM237K
LM237SP
-25C to 150C
LM337
LM337K
LM337SP
0C to 125C
TO-3
TO-220
LM137-LM237-LM337
3/13
ELECTRICAL CHARACTERISTICS OF LM137/LM237 (T
J
= -55 to 150C for LM137,
T
J
= -25 to 150C for LM237, V
I
-V
O
= 5V, I
O
= 0.5 A unless otherwise specified).
Notes: 1. Although power dissipation is internally limited, these specifications are applicable for power dissipation of:
15 W for TO-220 and 20 W for TO-3 Package; I
O(max)
is : 1.5 A
2. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage
due to heating effects are covered under the specification for thermal regulation.
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
ref
Reference Voltage
T
a
= 25C
-1.225
-1.25
-1.275
V
|V
I
- V
O
| = 3 to 40 V,
T
J
= T
min
to T
max
|I
O
| = 10mA to |I
O(max)
|
P
P
max
-1.2
-1.25
-1.3
K
VI
Line Regulation (Note 2)
T
a
= 25C
|V
I
- V
O
| = 3 to 40 V
I
O
= 0.1 A
0.01
0.02
%/V
I
O
= 20 mA
0.01
0.02
K
VO
Load Regulation (Note 2)
T
a
= 25C
|I
O
| = 10mA to |I
O(max)
|
|V
O
|
5 V
15
25
mV
|V
O
|
5 V
0.3
0.5
%
Thermal Regulation
T
a
= 25C, pulse 10 ms
0.002
0.02
%/W
I
adj
Adjustment Pin Current
65
100
A
I
adj
Adjustment Pin Current
Change
T
a
= 25C,
|I
O
| = 10 mA to |I
O(max)
|
|V
I
- V
O
| = 3 to 40 V
2
5
A
K
VI
Line Regulation (Note 2)
|V
I
- V
O
| = 3 to 40 V
0.02
0.05
%/V
K
VO
Load Regulation (Note 2)
|I
O
| = 10mA to |I
O(max)
|
|V
O
|
5 V
20
50
mV
|V
O
|
5 V
0.3
1
%
|I
O(min)
| Minimum Load Current
|V
I
- V
O
|
40 V
2.5
5
mA
|V
I
- V
O
|
10 V
1.2
3
I
OS
Short Circuit Output Current |V
I
- V
O
|
15 V
1.5
2.2
A
|V
I
- V
O
| = 40 V, T
J
=2 5C
0.24
0.4
V
NO
RMS Output Noise
(% of V
O
)
T
a
= 25C
f = 10 Hz to 10 KHz
0.003
%
R
vf
Ripple Rejection Ratio
V
O
= -10 V, f = 120 Hz
60
dB
C
adj
= 10 F
66
77
K
VT
Temperature Stability
0.6
%
K
VH
Long Term Stability
T
a
= 125C, 1000 H
0.3
1
%
LM137-LM237-LM337
4/13
ELECTRICAL CHARACTERISTICS OF LM337 (T
J
= 0 to 150C unless otherwise specified).
Notes: 1. Although power dissipation is internally limited, these specifications are applicable for power dissipation of:
15 W for TO-220 and 20 W for TO-3 Package; I
O(max)
is : 1.5 A
2. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage
due to heating effects are covered under the specification for thermal regulation.
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
ref
Reference Voltage
T
a
= 25C
-1.213
-1.25
-1.287
V
|V
I
- V
O
| = 3 to 40 V,
T
J
= T
min
to T
max
|I
O
| = 10mA to |I
O(max)
|
P
P
max
-1.2
-1.25
-1.3
K
VI
Line Regulation (Note 2)
T
a
= 25C
|V
I
- V
O
| = 3 to 40 V
I
O
= 0.1 A
0.01
0.04
%/V
I
O
= 20 mA
0.01
0.04
K
VO
Load Regulation (Note 2)
T
a
= 25C
|I
O
| = 10mA to |I
O(max)
|
|V
O
|
5 V
15
50
mV
|V
O
|
5 V
0.3
1
%
Thermal Regulation
T
a
= 25C, pulse 10 ms
0.003
0.04
%/W
I
adj
Adjustment Pin Current
65
100
A
I
adj
Adjustment Pin Current
Change
T
a
= 25C,
|I
O
| = 10 mA to |I
O(max)
|
|V
I
- V
O
| = 3 to 40 V
2
5
A
K
VI
Line Regulation (Note 2)
|V
I
- V
O
| = 3 to 40 V
0.02
0.07
%/V
K
VO
Load Regulation (Note 2)
|I
O
| = 10mA to |I
O(max)
|
|V
O
|
5 V
20
70
mV
|V
O
|
5 V
0.3
1.5
%
|I
O(min)
| Minimum Load Current
|V
I
- V
O
|
40 V
2.5
10
mA
|V
I
- V
O
|
10 V
1.5
6
I
OS
Short Circuit Output Current |V
I
- V
O
|
15 V
1.5
2.2
A
|V
I
- V
O
| = 40 V, T
J
=2 5C
0.15
0.4
V
NO
RMS Output Noise
(% of V
O
)
T
a
= 25C
f = 10 Hz to 10 KHz
0.003
%
R
vf
Ripple Rejection Ratio
V
O
= -10 V, f = 120 Hz
60
dB
C
adj
= 10 F
66
77
K
VT
Temperature Stability
0.6
%
K
VH
Long Term Stability
T
a
= 125C, 1000 H
0.3
1
%
LM137-LM237-LM337
5/13
Figure 1 : Load Regulation
Figure 2 : Current Limit
Figure 3 : Adjustment Current
Figure 4 : Dropout Voltage
Figure 5 : Temperature Stability
Figure 6 : Minimum Operating Current
LM137-LM237-LM337
6/13
Figure 7 : Ripple Rejection Versus Output
Voltage
Figure 8 : Ripple Rejection Versus Frequency
Figure 9 : Ripple Rejection Versus Output
Current
Figure 10 : Output Impedance
Figure 11 : Line Transient Response
Figure 12 : Load Transient Response
LM137-LM237-LM337
7/13
THERMAL REGULATION
When power is dissipated in an IC, a temperature
gradient occurs across the IC chip affecting the
individual IC circuit components. With an IC
regulator, this gradient can be especially severe
since power dissipation is large.
Thermal
regulation
is
the
effect
of
these
temperature gradients on output voltage (in
percentage output change) per watt of power
change in a specified time. Thermal regulation
error is independent of electrical regulation or
temperature coefficient, and occurs within 5ms to
50ms after a change in power dissipation.
Thermal regulation depends on IC layout as well
as electrical design. The thermal regulation of a
voltage regulator is defined as the percentage
change of V
O
, per watt, within the first 10ms after
a step of power, is applied.
The LM137 specification is 0.02%/W max.In figure
1, a typical LM337's output drifts only 3mV for
0.03% of V
O
= 10V) when a 10W pulse is
applied for 10ms. This performance is thus well
inside the specification limit of 0.02%/W x 10W =
0.2% max. When the 10W pulse is ended the
thermal regulation again shows a 3mV step as the
LM137 chip cools off. Note that the load regulation
error of about 8mV(0.08%) is additional to the
thermal regulation error.
In figure 2, when the 10W pulse is applied for
100ms, the output drifts only slightly beyond the
drift in the first 10ms and the thermal error stays
well within 0.1% (10mV).
Figure 13 : TYPICAL OUTPUT DRIFT
LM337, VO = -10V, V
I
- V
O
= - 40V, I
L
= 0A
0.25A
0A. Vertical sensitivity 5mV/div.
Figure 14 : TYPICAL OUTPUT DRIFT
LM337, VO = -10V, V
I
- V
O
= - 40V, I
L
= 0A
0.25A
0A. Horizontal sensitivity 5msN/div.
LM137-LM237-LM337
8/13
TYPICAL APPLICATIONS
ADJUSTABLE NEGATIVE VOLTAGE REGULATOR
* C1 = 1 F solid tantalum or 10F aluminium electrolytic required for stability.
** C2 = 1 F solid tantalum is required only if regulator is more than 10 cm from power supply filter capacitors
ADJUSTABLE LAB VOLTAGE REGULATOR
* The 10 F capacitors are optimal to improve ripple rejection.
LM137-LM237-LM337
9/13
CURRENT REGULATOR
NEGATIVE REGULATOR WITH PROTECTION DIODES
* When CL is larger than 20 F, D1 protects the LM137 in case the input supply is shorted.
** When C2 is larger than 10F and VO is larger than -25V, D2 protects the LM137 in case the output is shorted.
LM137-LM237-LM337
10/13
* - 5.2V REGULATOR WITH ELECTRONIC SHUTDOWN
* Minimum output = - 1.3V when control input is low.
CURRENT REGULATOR
LM137-LM237-LM337
11/13
DIM.
mm.
inch
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
11.85
0.466
B
0.96
1.05
1.10
0.037
0.041
0.043
C
1.70
0.066
D
8.7
0.342
E
20.0
0.787
G
10.9
0.429
N
16.9
0.665
P
26.2
1.031
R
3.88
4.09
0.152
0.161
U
39.5
1.555
V
30.10
1.185
TO-3 MECHANICAL DATA
P003C/C
E
B
R
C
D
A
P
G
N
V
U
O
LM137-LM237-LM337
12/13
DIM.
mm.
inch
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
4.40
4.60
0.173
0.181
C
1.23
1.32
0.048
0.051
D
2.40
2.72
0.094
0.107
D1
1.27
0.050
E
0.49
0.70
0.019
0.027
F
0.61
0.88
0.024
0.034
F1
1.14
1.70
0.044
0.067
F2
1.14
1.70
0.044
0.067
G
4.95
5.15
0.194
0.203
G1
2.4
2.7
0.094
0.106
H2
10.0
10.40
0.393
0.409
L2
16.4
0.645
L4
13.0
14.0
0.511
0.551
L5
2.65
2.95
0.104
0.116
L6
15.25
15.75
0.600
0.620
L7
6.2
6.6
0.244
0.260
L9
3.5
3.93
0.137
0.154
DIA.
3.75
3.85
0.147
0.151
TO-220 MECHANICAL DATA
P011C
LM137-LM237-LM337
13/13
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
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