NSC LM337LZ

LM337L
3-Terminal Adjustable Regulator
General Description
The LM337L is an adjustable 3-terminal negative voltage
regulator capable of supplying 100 mA over a 1.2V to 37V
output range. It is exceptionally easy to use and requires
only two external resistors to set the output voltage. Furthermore, both line and load regulation are better than standard
fixed regulators. Also, the LM337L is packaged in a standard
TO-92 transistor package which is easy to use.
In addition to higher performance than fixed regulators, the
LM337L offers full overload protection. 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.
Normally, only a single 1 µF solid tantalum output capacitor
is needed unless the device is situated more than 6 inches
from the input filter capacitors, in which case an input bypass
is needed. A larger output capacitor can be added to improve
transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are
difficult to achieve with standard 3-terminal regulators.
Besides replacing fixed regulators, the LM337L is useful in a
wide variety of other applications. Since the regulator is
“floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as
long as the maximum input-to-output differential is not exceeded.
Also, it makes an especially simple adjustable switching
regulator, a programmable output regulator, or by connecting
a fixed resistor between the adjustment and output, the
LM337L can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping
the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current.
The LM337L is available in a standard TO-92 transistor
package and a SO-8 surface mount package. The LM337L is
rated for operation over a −25˚C to +125˚C range.
For applications requiring greater output current in excess of
0.5A and 1.5A, see LM137 series data sheets. For the positive complement, see series LM117 and LM317L data
sheets.
Features
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Adjustable output down to 1.2V
Guaranteed 100 mA output current
Line regulation typically 0.01%/V
Load regulation typically 0.1%
Current limit constant with temperature
Eliminates the need to stock many voltages
Standard 3-lead transistor package
80 dB ripple rejection
Output is short circuit protected
Connection Diagram
DS009134-1
Bottom View
DS009134-2
Top View
Order Number LM337LM or LM337LZ
See NS Package Number M08A or Z03A
© 1999 National Semiconductor Corporation
DS009134
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LM337L 3-Terminal Adjustable Regulator
May 1998
Absolute Maximum Ratings (Note 1)
Storage Temperature
Lead Temperature
(Soldering, 10 sec.)
Plastic Package (Soldering 4 sec.)
ESD rating to be determined.
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Dissipation
Input–Output Voltage Differential
Operating Junction
Temperature Range
Internally Limited
40V
−55˚C to +150˚C
300˚C
260˚C
−25˚C to +125˚C
Electrical Characteristics (Note 2)
Parameter
Line Regulation
Load Regulation
Thermal Regulation
Conditions
TA = 25˚C, 3V ≤ |VIN − VOUT| ≤ 40V,
Min
Max
Units
0.04
%/V
(Note 3)
TA = 25˚C, 5 mA ≤ IOUT ≤ IMAX, (Note 3)
TA = 25˚C, 10 ms Pulse
0.1
0.5
%
0.04
0.2
%/W
50
100
µA
5 mA ≤ IL ≤ 100 mA
0.2
5
µA
1.25
1.30
V
%/V
Adjustment Pin Current
Adjustment Pin Current Change
Typ
0.01
3V ≤ |VIN − VOUT| ≤ 40V
Reference Voltage
3V ≤ |VIN − VOUT| ≤ 40V, (Note 4)
1.20
10 mA ≤ IOUT ≤ 100 mA, P ≤ 625 mW
Line Regulation
3V ≤ |VIN − VOUT| ≤ 40V, (Note 3)
0.02
0.07
Load Regulation
5 mA ≤ IOUT ≤ 100 mA, (Note 3)
0.3
1.5
Temperature Stability
TMIN ≤ Tj ≤ TMAX
0.65
Minimum Load Current
|VIN − VOUT| ≤ 40V
3.5
5
mA
3V ≤ |VIN − VOUT| ≤ 15V
2.2
3.5
mA
100
200
320
mA
25
50
120
mA
Current Limit
3V ≤ |VIN − VOUT| ≤ 13V
|VIN − VOUT| = 40V
Ripple Rejection Ratio
TA = 25˚C, 10 Hz ≤ f ≤ 10 kHz
VOUT = −10V, F = 120 Hz, CADJ = 0
CADJ = 10 µF
Long-Term Stability
TA = 125˚C
Rms Output Noise, % of VOUT
66
%
%
0.003
%
65
dB
80
0.3
dB
1
%
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits.
Note 2: Unless otherwise specified, these specifications apply −25˚C ≤ Tj ≤ + 125˚C for the LM337L; |VIN − VOUT| = 5V and IOUT = 40 mA. Although power dissipation is internally limited, these specifications are applicable for power dissipations up to 625 mW. IMAX is 100 mA.
Note 3: 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.
Note 4: Thermal resistance of the TO-92 package is 180˚C/W junction to ambient with 0.4" leads from a PC board and 160˚C/W junction to ambient with 0.125" lead
length to PC board. The M package θJA is 180˚C/W in still air.
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Typical Applications
1.2V-25V Adjustable Regulator
Regulator with Trimmable Output Voltage
DS009134-3
Full output current not available at high input-output voltages
DS009134-4
Trim Procedure:
— If VOUT is −23.08V or bigger, cut out R3 (if smaller, don’t cut it out).
— Then if VOUT is −22.47V or bigger, cut out R4 (if smaller, don’t).
— Then if VOUT is −22.16V or bigger, cut out R5 (if smaller, don’t).
This will trim the output to well within 1% of −22.00 VDC, without any of the
expense or trouble of a trim pot (see LB-46). Of course, this technique can
be used at any output voltage level.
†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
3
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Physical Dimensions
inches (millimeters) unless otherwise noted
SO-8 Plastic Package (M)
Order Number LM337LM
NS Package Number M08A
TO-92 Plastic Package (Z)
Order Number LM337LZ
NS Package Number Z03A
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LM337L 3-Terminal Adjustable Regulator
Notes
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