Three-terminal adjustable negative voltage regulators
■ Output voltage adjustable down to V
■
1.5 A guaranteed output current
■ 0.3%/V typical load regulation
■ 0.01%/V typical line regulation
■ Current limit constant with temperature
■ Ripple rejection: 77 dB
■ Standard 3-lead transistor packages
■ Excellent thermal regulation: 0.002%/V
■ 50 ppm/°C temperature coefficient
REF
Description
The LM137 series are adjustable 3-terminal
negative voltage regulators capable of supplying
in excess -1.5 A over a -1.2 to -37 V 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.
Note:Absolute maximum ratings are those values beyond which damage to the device may occur.
Table 3.Thermal data
Output current1.5A
O
Power dissipationInternally limited
D
Storage temperature range- 65 to 150°C
Operating junction temperature range
LM137- 55 to 150
LM3370 to 125
Functional operation under these condition is not implied.
°C
SymbolParameterTO-220TO-3Unit
R
R
thJC
thJA
Thermal resistance junction-case max.34°C/W
Thermal resistance junction-ambient max.7035°C/W
Doc ID 2167 Rev 45/18
Electrical characteristicsLM137, LM337
4 Electrical characteristics
TJ = -55 to 150 °C, VI - VO = 5 V, IO = 0.5 A unless otherwise specified.
Table 4.Electrical characteristics of LM137
SymbolParameterTest conditionsMin.Typ.Max.Unit
Ta = 25°C-1.225-1.25-1.275
V
K
I
ΔI
K
|I
O(min)
V
R
K
K
1. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output
Reference voltage
REF
K
VI
VO
Line regulation
Load regulation
(1)
(1)
Thermal regulationT
Adjustment pin current65100µA
ADJ
Adjustment pin current
ADJ
change
K
VI
VO
Line regulation
Load regulation
(1)
(1)
| Minimum load current
I
Short circuit output current
OS
RMS output noise
NO
(% of V
Ripple rejection ratio
VF
Temperature stability0.6%
VT
Long term stabilityTa = 125°C, 1000 H0.31%
VH
voltage due to heating effects are covered under the specification for thermal regulation.
)
O
|V
- VO| = 3 to 40 V, TJ = T
I
|IO| = 10mA to |I
O(max)
| P ≤ P
Ta = 25°C
- VO| = 3 to 40 V
|V
I
Ta = 25°C
|IO| = 10mA to |I
= 25°C, pulse 10 ms0.0020.02%/W
a
O(max)
|
Ta = 25°C, |IO| = 10 mA to |I
|VI - VO| = 3 to 40 V
to T
min
max
max
-1.2-1.25-1.3
IO = 0.1 A0.010.02
= 20 mA0.010.02
I
O
| ≤ 5 V1525mV
|V
O
| ≥ 5 V0.30.5%
|V
O
|
O(max)
25µA
|VI - VO| = 3 to 40 V0.020.05%/V
|VO| ≤ 5 V2050mV
|IO| = 10mA to |I
|V
- VO| ≤ 40 V2.55
I
- VO| ≤ 10 V1.23
|V
I
|V
- VO| ≤ 15 V1.52.2
I
- VO| = 40 V, TJ =25°C0.240.4
|V
I
= 25°C, f = 10 Hz to 10 kHz0.003%
T
a
V
= -10 V, f = 120 Hz60
O
= 10 µF6677
C
ADJ
O(max)
|
| ≥ 5 V0.31%
|V
O
V
%/V
mA
A
dB
= 0 to 150 °C unless otherwise specified.
T
J
6/18Doc ID 2167 Rev 4
LM137, LM337Electrical characteristics
Table 5.Electrical characteristics of LM337
SymbolParameterTest conditionsMin.Typ.Max.Unit
Ta = 25°C-1.213-1.25-1.287
V
K
I
ΔI
K
|I
O(min)
V
R
K
K
1. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output
Reference voltage
REF
K
VI
VO
Line regulation
Load regulation
(1)
(1)
Thermal regulationT
Adjustment pin current65100µA
ADJ
Adjustment pin current
ADJ
change
K
VI
VO
Line regulation
Load regulation
(1)
(1)
| Minimum load current
I
Short circuit output current
OS
RMS output noise
NO
(% of VO)
Ripple rejection ratio
VF
Temperature stability0.6%
VT
Long term stabilityTa = 125°C, 1000 H0.31%
VH
voltage due to heating effects are covered under the specification for thermal regulation.
|V
- VO| = 3 to 40 V, TJ = T
I
|IO| = 10mA to |I
O(max)
|, P ≤ P
Ta = 25°C
- VO| = 3 to 40 V
|V
I
Ta = 25°C
|IO| = 10mA to |I
= 25°C, pulse 10 ms0.0030.04%/W
a
O(max)
|
Ta = 25°C, |IO| = 10 mA to |I
- VO| = 3 to 40 V
|V
I
to T
min
max
max
-1.2-1.25-1.3
IO = 0.1 A0.010.04
= 20 mA0.010.04
I
O
| ≤ 5 V1550mV
|V
O
| ≥ 5 V0.31%
|V
O
|
O(max)
25µA
|VI - VO| = 3 to 40 V0.020.07%/V
|VO| ≤ 5 V2070mV
|IO| = 10mA to |I
|V
- VO| ≤ 40 V2.510
I
- VO| ≤ 10 V1.56
|V
I
|V
- VO| ≤ 15 V1.52.2
I
- VO| = 40 V, TJ =2 5°C0.150.4
|V
I
= 25°C, f = 10 Hz to 10 kHz0.003%
T
a
V
= -10 V, f = 120 Hz60
O
= 10 µF6677
C
ADJ
O(max)
|
| ≥ 5 V0.31.5%
|V
O
V
%/V
mA
A
dB
Doc ID 2167 Rev 47/18
Typical characteristicsLM137, LM337
5 Typical characteristics
Figure 3.Load regulationFigure 4.Current limit
Figure 5.Adjustment currentFigure 6.Dropout voltage
Figure 7.Temperature stabilityFigure 8.Minimum operating current
8/18Doc ID 2167 Rev 4
LM137, LM337Typical characteristics
Figure 9.Ripple rejection vs. output voltageFigure 10. Ripple rejection vs. frequency
Figure 11. Ripple rejection vs. output currentFigure 12. Output impedance
Figure 13. Line transient responseFigure 14. Load transient response
Doc ID 2167 Rev 49/18
Thermal regulationLM137, LM337
6 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 5
ms to 50 ms 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
The LM137 specification is 0.02%/W max. In Figure 1, a typical LM337’s output drifts only 3
mV for 0.03% of V
thus well inside the specification limit of 0.02%/W x 10 W = 0.2% max. When the 10 W pulse
is ended the thermal regulation again shows a 3 mV step as 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 10 W 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).
O
, per watt, within the first 10ms after a step of power, is applied.
O
= – 10 V) when a 10 W pulse is applied for 10 ms. This performance is
10/18Doc ID 2167 Rev 4
LM137, LM337Typical application
7 Typical application
Figure 15. Adjustable negative voltage regulator
* C1 = 1 µF solid tantalum or 10 µF aluminium electrolytic required for stability.
** C2 = 1 µF solid tantalum is required only if regulator is more than 10 cm from power supply filter capacitors
Figure 16. Adjustable lab voltage regulator
* The 10 µF capacitors are optimal to improve ripple rejection.
Doc ID 2167 Rev 411/18
Typical applicationLM137, LM337
Figure 17. Current regulator
Figure 18. Negative regulator with protection diodes
* When CL is larger than 20 µF, D1 protects the LM137 in case the input supply is shorted.
** When C2 is larger than 10 µF and V
shorted.
is larger than - 25 V, D2 protects the LM137 in case the output is
O
12/18Doc ID 2167 Rev 4
LM137, LM337Typical application
Figure 19. - 5.2 V regulator with electronic shutdown
1. Minimum output = - 1.3 V when control input is low.
Figure 20. Current regulator
(1)
Doc ID 2167 Rev 413/18
Package mechanical dataLM137, LM337
8 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK
®
packages, depending on their level of environmental compliance. ECOPACK®
®
is an ST trademark.
14/18Doc ID 2167 Rev 4
LM137, LM337Package mechanical data
TO-220 mechanical data
Dim.
A4.404.600.1730.181
C1.231.320.0480.051
D2.402.720.0940.107
D11.270.050
E0.490.700.0190.027
F0.610.880.0240.034
F11.141.700.0440.067
F21.141.700.0440.067
G4.955.150.1940.203
G12.42.70.0940.106
H210.010.400.3930.409
L216.40.645
L413.014.00.5110.551
L52.652.950.1040.116
L615.2515.750.6000.620
L76.26.60.2440.260
L93.53.930.13 70.154
DIA.3.753.850.1470.151
Min.Typ.Max.Min.Typ.Max.
mm.inch.
P011C
Doc ID 2167 Rev 415/18
Package mechanical dataLM137, LM337
TO-3 mechanical data
Dim.
A11.850.466
B0.961.051.100.0370.0410.043
C1.700.066
D8.70.342
E20.00.787
G10.90.429
N16.90.665
P26.21.031
R3.884.090.1520.161
U39.51.555
V30.101.185
Min.Typ.Max.Min.Typ.Max.
mm.inch.
P
A
G
U
V
N
O
B
D
C
E
R
P003C/C
16/18Doc ID 2167 Rev 4
LM137, LM337Revision history
9 Revision history
Table 6.Document revision history
DateRevisionChanges
19-Jul-20041First issue.
10-Jan-20052Modified pin connection for TO-3.
17-Jul-20083Added: Table 1 on page 1.
03-Oct-20114Modified: Table 1 on page 1.
Doc ID 2167 Rev 417/18
LM137, LM337
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