LM137/LM337
3-Terminal Adjustable Negative Regulators
General Description
The LM137/LM337 are adjustable 3-terminal negative volt-
age regulators capable of supplying in excess of −1.5A over
an output voltage range of −1.2V to −37V. These regulators
are exceptionally easy to apply, requiring only 2 external re-
sistors to set the output voltage and 1 output capacitor for
frequency compensation. The circuit design has been opti-
mized for excellent regulation and low thermal transients.
Further, the LM137 series features internal current limiting,
thermal shutdown and safe-area compensation, making
them virtually blowout-proof against overloads.
The LM137/LM337 serve a wide variety of applications in-
cluding local on-card regulation, programmable-output volt-
age regulation or precision current regulation. The LM137/
LM337 are ideal complements to the LM117/LM317
adjustable positive regulators.
Features
nOutput voltage adjustable from −1.2V to −37V
n1.5A output current guaranteed, −55˚C to +150˚C
nLine regulation typically 0.01%/V
nLoad regulation typically 0.3%
nExcellent thermal regulation, 0.002%/W
n77 dB ripple rejection
nExcellent rejection of thermal transients
n50 ppm/˚C temperature coefficient
nTemperature-independent current limit
nInternal thermal overload protection
nP
+
Product Enhancement tested
nStandard 3-lead transistor package
nOutput is short circuit protected
LM137 Series Packages and Power
Capability
Rated Design
Device Package Power Load
Dissipation Current
LM137/337 TO-3 (K) 20W 1.5A
TO-39 (H) 2W 0.5A
LM337 TO-220 (T) 15W 1.5A
LM337 SOT-223
(MP) 2W 1A
Typical Applications Comparison between SOT-223 and
D-Pak (TO-252) Packages
Adjustable Negative Voltage Regulator
DS009067-1
Full output current not available at high input-output voltages
†C1 =1 µF solid tantalum or 10 µF aluminum electrolytic required for
stability
*C2 =1 µF solid tantalum is required only if regulator is more than 4" from
power-supply filter capacitor
Output capacitors in the range of 1 µF to 1000 µF of aluminum or tantalum
electrolytic are commonly used to provide improved output impedance and
rejection of transients
DS009067-31
Scale 1:1
May 1999
LM137/LM337 3-Terminal Adjustable Negative Regulators
© 1999 National Semiconductor Corporation DS009067 www.national.com
Absolute Maximum Ratings (Notes 1, 4)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Dissipation Internally Limited
Input-Output Voltage Differential 40V
Operating Junction Temperature Range
LM137 −55˚C to +150˚C
LM337 0˚C to +125˚C
Storage Temperature −65˚C to +150˚C
Lead Temperature (Soldering, 10 sec.) 300˚C
Plastic Package (Soldering, 4 sec.) 260˚C
ESD Rating 2k Volts
Electrical Characteristics
(Note 1)
Parameter Conditions LM137 LM337 Units
Min Typ Max Min Typ Max
Line Regulation T
j
=25˚C, 3V ≤|V
IN
−V
OUT
|≤40V 0.01 0.02 0.01 0.04 %/V
(Note 2) I
L
=10 mA
Load Regulation T
j
=25˚C, 10 mA ≤I
OUT
≤I
MAX
0.3 0.5 0.3 1.0 %
Thermal Regulation T
j
=25˚C, 10 ms Pulse 0.002 0.02 0.003 0.04 %/W
Adjustment Pin Current 65 100 65 100 µA
Adjustment Pin Current Charge 10 mA ≤I
L
≤I
MAX
25 25µA
3.0V ≤|V
IN
−V
OUT
|≤40V,
T
A
=25˚C
Reference Voltage T
j
=25˚C (Note 3) −1.225 −1.250 −1.275 −1.213 −1.250 −1.287 V
3V ≤|V
IN
−V
OUT
|≤40V, (Note 3) −1.200 −1.250 −1.300 −1.200 −1.250 −1.300 V
10 mA ≤I
OUT
≤I
MAX
,P≤P
MAX
Line Regulation 3V ≤|V
IN
−V
OUT
|≤40V, (Note 2) 0.02 0.05 0.02 0.07 %/V
Load Regulation 10 mA ≤I
OUT
≤I
MAX
, (Note 2) 0.3 1 0.3 1.5 %
Temperature Stability T
MIN
≤T
j
≤T
MAX
0.6 0.6 %
Minimum Load Current |V
IN
−V
OUT
|≤40V 2.5 5 2.5 10 mA
|V
IN
−V
OUT
|≤10V 1.2 3 1.5 6 mA
Current Limit |V
IN
−V
OUT
|≤15V
K, MP and T Package 1.5 2.2 3.5 1.5 2.2 3.7 A
H Package 0.5 0.8 1.8 0.5 0.8 1.9 A
|V
IN
−V
OUT
|=40V, T
j
=25˚C
K, MP and T Package 0.24 0.4 0.15 0.4 A
H Package 0.15 0.17 0.10 0.17 A
RMS Output Noise, %of V
OUT
T
j
=25˚C, 10 Hz ≤f≤10 kHz 0.003 0.003 %
Ripple Rejection Ratio V
OUT
=−10V, f =120 Hz 60 60 dB
C
ADJ
=10 µF 66 77 66 77 dB
Long-Term Stability T
j
=125˚C, 1000 Hours 0.3 1 0.3 1 %
Thermal Resistance, Junction to
Case H Package 12 15 12 15 ˚C/W
K Package 2.3 3 2.3 3 ˚C/W
T Package 4 ˚C/W
Thermal Resistance, Junction to
Ambient (No Heat Sink) H Package 140 140 ˚C/W
K Package 35 35 ˚C/W
T Package
MP Package 50
170 ˚C/W
˚C/W
Note 1: Unless otherwise specified, these specifications apply −55˚C ≤Tj≤+150˚C for the LM137, 0˚C ≤Tj≤+125˚C for the LM337; VIN −V
OUT =5V; and IOUT
=0.1A for the TO-39 package and IOUT =0.5A for the TO-3, SOT-223 and TO-220 packages. Although power dissipation is internally limited, these specifications
are applicable for power dissipations of 2W for the TO-39 and SOT-223 (see Application Hints), and 20W for the TO-3, and TO-220. IMAX is 1.5A for the TO-3,
SOT-223 and TO-220 packages, and 0.2A for the TO-39 package.
Note 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 cov-
ered under the specification for thermal regulation. Load regulation is measured on the output pin at a point
1
⁄
8
" below the base of the TO-3 and TO-39 packages.
Note 3: Selected devices with tightened tolerance reference voltage available.
Note 4: Refer to RETS137H drawing for LM137H or RETS137K drawing for LM137K military specifications.
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Schematic Diagram
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 espe-
cially severe since power dissipation is large. Thermal regu-
lation 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 inde-
pendent of electrical regulation or temperature coefficient,
and occurs within 5 ms to 50 ms after a change in power dis-
sipation. Thermal regulation depends on IC layout as well as
electrical design. The thermal regulation of a voltage regula-
tor is defined as the percentage change of V
OUT
, per Watt,
within the first 10 ms after a step of power is applied. The
LM137’s specification is 0.02%/W, max.
In
Figure 1
, a typical LM137’s output drifts only 3 mV (or
0.03%of V
OUT
=−10V) when a 10W pulse is applied for
10 ms. 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 showsa3mVstep at
the LM137 chip cools off. Note that the load regulation error
of about 8 mV (0.08%) is additional to the thermal regulation
error. In
Figure 2
, when the 10W pulse is applied for 100 ms,
the output drifts only slightly beyond the drift in the first
10 ms, and the thermal error stays well within 0.1%(10 mV).
DS009067-2
DS009067-3
LM137, VOUT =−10V
VIN −V
OUT =−40V
IIL =0A →0.25A →0A
Vertical sensitivity, 5 mV/div
FIGURE 1.
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Thermal Regulation (Continued)
Connection Diagrams
Application Hints
When a value for θ
(H−A)
is found using the equation shown,
a heatsink must be selected that has a value that is less than
or equal to this number.
HEATSINKING SOT-223 PACKAGE PARTS
The SOT-223 (“MP”) packages use a copper plane on the
PCB and the PCB itself as a heatsink. To optimize the heat
sinking ability of the plane and PCB, solder the tab of the
package to the plane.
Figures 3, 4
show the information for the SOT-223 package.
Figure 4
assumes a θ
(J−A)
of 75˚C/W for 1 ounce copper and
51˚C/W for 2 ounce copper and a maximum junction tem-
perature of 125˚C.
DS009067-4
LM137, VOUT =−10V
VIN −V
OUT =−40V
IL=0A →0.25A →0A
Horizontal sensitivity, 20 ms/div
FIGURE 2.
TO-3
Metal Can Package
DS009067-5
Case is Input
Bottom View
Order Number LM137K/883
LM137KPQML and LM137KPQMLV(Note 5)
See NS Package Number K02C
Order Number LM337K STEEL
See NS Package Number K02A
TO-39
Metal Can Package
DS009067-6
Case Is Input
Note 5: See STD Mil DWG 5962P99517 for Radiation Tolerant Devices
Bottom View
Order Number LM137H, LM137H/883 or LM337H
LM137HPQML and LM137HPQMLV(Note 5)
See NS Package Number H03A
TO-220
Plastic Package
DS009067-7
Front View
Order Number LM337T
See NS Package Number T03B
3-Lead SOT-223
DS009067-34
Front View
Order Number LM337IMP
Package Marked N02ASee NS Package Number MA04A
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Application Hints (Continued)
Please see AN1028 for power enhancement techniques to
be used with the SOT-223 package.
Typical Applications
DS009067-32
FIGURE 3. θ
(J−A)
vs Copper (2 ounce) Area for the
SOT-223 Package
DS009067-33
FIGURE 4. Maximum Power Dissipation vs T
AMB
for
the SOT-223 Package
Adjustable Lab Voltage Regulator
DS009067-9
Full output current not available
at high input-output voltages
*The 10 µF capacitors are optional to improve ripple rejection
Current Regulator
DS009067-11
Negative Regulator with Protection Diodes
DS009067-13
*When CLis larger than 20 µF, D1 protects the LM137 in case the input
supply is shorted
**When C2 is larger than 10 µF and −VOUT is larger than −25V, D2
protects the LM137 in case the output is shorted
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Typical Applications (Continued)
−5.2V Regulator with Electronic Shutdown*
DS009067-10
*Minimum output ≅−1.3V when control input is low
Adjustable Current Regulator
DS009067-12
High Stability −10V Regulator
DS009067-14
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Typical Performance Characteristics (K Steel and T Packages)
Load Regulation
DS009067-16
Current Limit
DS009067-17
Adjustment Current
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Dropout Voltage
DS009067-19
Temperature Stability
DS009067-20
Minimum Operating Current
DS009067-21
Ripple Rejection
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Ripple Rejection
DS009067-23
Ripple Rejection
DS009067-24
Output Impedance
DS009067-25
Line Transient Response
DS009067-26
Load Transient Response
DS009067-27
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Physical Dimensions inches (millimeters) unless otherwise noted
Metal Can Package (H)
Order Number LM137H, LM137H/883 or LM337H
NS Package Number H03A
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Metal Can Package (K)
Order Number LM337K STEEL
NS Package Number K02A
Mil-Aero Metal Can Package (K)
Order Number LM137K/883
NS Package Number K02C
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
3-Lead SOT-223 Package
Order Number LM337IMP
NS Package Number M04A
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
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COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
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whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
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TO-220 Plastic Package (T)
Order Number LM337T
NS Package Number T03B
LM137/LM337 3-Terminal Adjustable Negative Regulators
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
