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LM317L-N
SNVS775L – MARCH 2000 – REVISED JANUARY 2018
LM317L-N Wide VIN 100-mA Adjustable Voltage Regulator
1 Features
3 Description
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•
•
•
•
•
•
•
•
•
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The LM317L-N is an adjustable positive voltage
regulator capable of supplying 100 mA over a 1.2-V
to 37-V output range. The LM317L-N is easy to use
and requires only two external resistors to set the
output voltage. Both line and load regulation are
better than standard fixed regulators. The LM317L-N
is available packaged in a standard, easy-to-use
TO-92 transistor package.
1
•
•
Adjustable Output Down to 1.2 V
100-mA Output Current
Capable of Handling up to 40V VIN
Line Regulation Typically 0.01% /V
Load Regulation Typically 0.1% /A
No Output Capacitor Required (†)
Current Limit Constant With Temperature
Eliminates the Need to Stock Many Voltages
Standard 3-Lead Transistor Package
80-dB Ripple Rejection
Available in 3-Pin TO-92, 8-Pin SOIC, or 6-pin
DSBGA Packages
Output is Short-Circuit Protected
See AN-1112 (SNVA009) for DSBGA
Considerations
2 Applications
•
•
•
•
•
Automotive LED Lighting
Battery Chargers
Post Regulation for Switching Supplies
Constant-Current Regulators
Microprocessor Supplies
Schematic Diagram
The LM317L-N offers full overload protection.
Included on the chip are current limit, thermal
overload protection, and safe area protection.
Normally, no capacitors are required unless the
device is situated more than 6 inches from the input
filter capacitors, in which case an input bypass is
required.
The LM317L-N uses floating topology and sees only
the input-to-output differential voltage, therefore
supplies of several hundred volts can be regulated,
provided the maximum input-to-output differential is
not exceeded. The device makes a simple adjustable
switching regulator, a programmable output regulator,
or by connecting a fixed resistor between the
adjustment and output, the LM317L-N can be used
as a precision current regulator.
The LM317L-N is available in a standard 3-pin TO-92
transistor package, the 8-pin SOIC package, and 6pin DSBGA package. The LM317L-N is rated for
operation over a −40°C to 125°C range.
Device Information(1)
PART NUMBER
LM317L-N
PACKAGE
BODY SIZE (NOM)
TO-92 (3)
4.30 mm × 4.30 mm
SOIC (8)
3.91 mm × 4.90 mm
DSBGA (6)
1.68 mm × 1.019 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Full output current not available at high
input-output voltages
†Optional—improves transient response
*Needed if device is more than 6 inches
from filter capacitors
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM317L-N
SNVS775L – MARCH 2000 – REVISED JANUARY 2018
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Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
4
4
4
4
5
6
Absolute Maximum Rating .......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics ..........................................
Typical Characteristics ..............................................
Detailed Description .............................................. 8
7.1 Overview ................................................................... 8
7.2 Functional Block Diagram ......................................... 9
7.3 Feature Description................................................. 10
7.4 Device Functional Modes........................................ 10
8
Application and Implementation ........................ 12
8.1 Application Information............................................ 12
8.2 Typical Applications ............................................... 12
9 Power Supply Recommendations...................... 25
10 Layout................................................................... 25
10.1 Layout Guidelines ................................................. 25
10.2 Layout Examples................................................... 25
10.3 Thermal Considerations ........................................ 26
11 Device and Documentation Support ................. 27
11.1
11.2
11.3
11.4
11.5
Documentation Support ........................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
27
27
27
27
27
12 Mechanical, Packaging, and Orderable
Information ........................................................... 27
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision K (September 2015) to Revision L
Page
•
Changed TO-92 package view from top to bottom view ........................................................................................................ 3
•
Changed DSBGA package view from bump side down to top view ...................................................................................... 3
•
Removed duplicate Protection Diodes section and Regulator With Protection Diodes image from the Device
Functional Modes section..................................................................................................................................................... 10
Changes from Revision J (March 2013) to Revision K
•
Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1
Changes from Revision I (March 2013) to Revision J
•
2
Page
Page
Changed layout of National Data Sheet to TI format ........................................................................................................... 25
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5 Pin Configuration and Functions
LP Plastic Package
3-Pin TO-92
Bottom View
D Package
8-Pin SOIC
Top View
YPB Package
6-Pin DSBGA
Top View
YPB Package
6-Pin DSBGA
Laser Mark
Pin Functions
PIN
NAME
TO-92
SOIC
DSBGA
I/O
DESCRIPTION
VIN
3
1
C1
I
Supply input pin
VOUT
2
2, 3, 6, 7
A1
O
Voltage output pin
Output voltage adjustment pin. Connect to a resistor divider to set VO.
ADJ
1
4
B2
I
NC
—
5, 8
B1, A2, C2
—
No connection
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6 Specifications
6.1 Absolute Maximum Rating
(1) (2)
MIN
Power dissipation
MAX
Input-output voltage differential
−40
Operating junction temperature
Lead temperature (soldering, 4 seconds)
−55
Storage temperature, Tstg
(1)
(2)
UNIT
Internally Limited
40
V
125
°C
260
°C
150
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
6.2 ESD Ratings
V(ESD)
(1)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
(1)
VALUE
UNIT
±2000
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. Pins listed as ±2000
V may actually have higher performance.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
Operating temperature
MIN
MAX
UNIT
−40
125
°C
6.4 Thermal Information
LM317L-N
TO-92
THERMAL METRIC (1)
SOIC
DSBGA
6 PINS
UNIT
3 PINS
0.4-in
Leads
0.125-in
Leads
8 PINS
180
160
165
290
°C/W
RθJC(top) Junction-to-case (top) thermal resistance
—
80.6
—
—
°C/W
RθJB
Junction-to-board thermal resistance
—
—
—
—
°C/W
ψJT
Junction-to-top characterization parameter
—
24.7
—
—
°C/W
ψJB
Junction-to-board characterization parameter
—
135.8
—
—
°C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance
—
—
—
—
°C/W
RθJA
(1)
4
Junction-to-ambient thermal resistance
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
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6.5 Electrical Characteristics
(1)
PARAMETER
TEST CONDITIONS
Line regulation
TJ = 25°C, 3 V ≤ (VIN − VOUT) ≤ 40 V, IL ≤ 20 mA (2)
Load regulation
TJ = 25°C, 5 mA ≤ IOUT ≤ IMAX
Thermal regulation
TJ = 25°C, 10-ms Pulse
MIN
(2)
Adjustment pin current change
Reference voltage
3 V ≤ (VIN − VOUT) ≤ 40 V (3)
5 mA ≤ IOUT ≤ 100 mA, P ≤ 625 mW
Line regulation
3 V ≤ (VIN − VOUT) ≤ 40 V, IL ≤ 20 mA (2)
Load regulation
5 mA ≤ IOUT ≤ 100 mA
Temperature stability
TMIN ≤ TJ ≤ TMAX
Minimum load current
Current limit
RMS output noise, % of VOUT
Ripple rejection ratio
Long-term stability
(1)
(2)
(3)
UNIT
0.01
%/V
0.04
0.1% 0.5%
Adjustment pin current
5 mA ≤ IL ≤ 100 mA
3 V ≤ (VIN − VOUT) ≤ 40 V, P ≤ 625 mW
TYP MAX
1.2
(2)
0.04
0.2
%/W
50
100
μA
0.2
5
μA
1.25
1.3
V
0.02
0.07
%/V
0.3% 1.5%
0.65%
(VIN − VOUT) ≤ 40 V
3.5
5
3 V ≤ (VIN − VOUT) ≤ 15 V
1.5
2.5
100
200
300
25
50
150
3 V ≤ (VIN − VOUT) ≤ 13 V
(VIN − VOUT) = 40 V
TJ = 25°C, 10 Hz ≤ f ≤ 10 kHz
65
66
TJ = 125°C, 1000 Hours
mA
0.003%
VOUT = 10 V, f = 120 Hz, CADJ = 0
CADJ = 10 μF
mA
dB
80
0.3%
1%
Unless otherwise noted, these specifications apply: −25°C ≤ Tj ≤ 125°C for the LM317L-N; VIN − VOUT = 5 V 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.
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.
Thermal resistance of the TO-92 package is 180°C/W junction to ambient with 0.4-inch leads from a PCB and 160°C/W junction to
ambient with 0.125-inch lead length to PCB.
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6.6 Typical Characteristics
(Output capacitor = 0 μF unless otherwise noted.)
6
Figure 1. Load Regulation
Figure 2. Current Limit
Figure 3. Adjustment Current
Figure 4. Dropout Voltage
Figure 5. Reference Voltage Temperature Stability
Figure 6. Minimum Operating Current
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Typical Characteristics (continued)
(Output capacitor = 0 μF unless otherwise noted.)
Figure 7. Ripple Rejection
Figure 8. Ripple Rejection
Figure 9. Output Impedance
Figure 10. Line Transient Response
Figure 11. Load Transient Response
Figure 12. Thermal Regulation
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7 Detailed Description
7.1 Overview
In operation, the LM317L-N develops a nominal 1.25-V reference voltage, VREF, between the output and
adjustment terminal. The reference voltage is impressed across program resistor R1 and, because the voltage is
constant, a constant current I1 then flows through the output set resistor R2, giving an output voltage of:
(1)
Because the 100-μA current from the adjustment terminal represents an error term, the LM317L-N was designed
to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current
is returned to the output establishing a minimum load current requirement. If there is insufficient load on the
output, the output will rise.
Figure 13. Typical Application Circuit for Adjustable Regulator
8
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7.2 Functional Block Diagram
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7.3 Feature Description
7.3.1 Load Regulation
The LM317L-N is capable of providing extremely good load regulation but a few precautions are needed to
obtain maximum performance. The current set resistor connected between the adjustment terminal and the
output terminal (usually 240 Ω) must be tied directly to the output of the regulator rather than near the load. This
eliminates line drops from appearing effectively in series with the reference and degrading regulation. For
example, a 15-V regulator with 0.05-Ω resistance between the regulator and load will have a load regulation due
to line resistance of 0.05 Ω × IL. If the set resistor is connected near the load the effective line resistance will be
0.05 Ω (1 + R2/R1) or in this case, 11.5 times worse.
Figure 14 shows the effect of resistance between the regulator and 240-Ω set resistor.
With the TO-92 package, it is easy to minimize the resistance from the case to the set resistor, by using two
separate leads to the output pin. The ground of R2 can be returned near the ground of the load to provide
remote ground-sensing and improve load regulation.
Figure 14. Regulator With Line Resistance in Output Lead
7.4 Device Functional Modes
7.4.1 External Capacitors
An input bypass capacitor is recommended in case the regulator is more than 6 inches away from the usual large
filter capacitor. A 0.1-μF disc or 1-μF solid tantalum on the input is suitable input bypassing for almost all
applications. The device is more sensitive to the absence of input bypassing when adjustment or output
capacitors are used, but the above values will eliminate the possibility of problems.
The adjustment terminal can be bypassed to ground on the LM317L-N to improve ripple rejection and noise. This
bypass capacitor prevents ripple and noise from being amplified as the output voltage is increased. With a 10-μF
bypass capacitor 80-dB ripple rejection is obtainable at any output level. Increases over 10-μF do not appreciably
improve the ripple rejection at frequencies above 120 Hz. If the bypass capacitor is used, it is sometimes
necessary to include protection diodes to prevent the capacitor from discharging through internal low current
paths and damaging the device.
In general, the best type of capacitors to use is solid tantalum. Solid tantalum capacitors have low impedance
even at high frequencies. Depending upon capacitor construction, it takes about 25 μF in aluminum electrolytic to
equal 1-μF solid tantalum at high frequencies. Ceramic capacitors are also good at high frequencies; but some
types have a large decrease in capacitance at frequencies around 0.5 MHz. For this reason, a 0.01-μF disc may
seem to work better than a 0.1-μF disc as a bypass.
Although the LM317L-N is stable with no output capacitors, like any feedback circuit, certain values of external
capacitance can cause excessive ringing. This occurs with values between 500 pF and 5000 pF. A 1-μF solid
tantalum (or 25-μF aluminum electrolytic) on the output swamps this effect and insures stability.
7.4.2 Protection Diodes
When external capacitors are used with any IC regulator it is sometimes necessary to add protection diodes to
prevent the capacitors from discharging through low current points into the regulator. Most 10-μF capacitors have
low enough internal series resistance to deliver 20-A spikes when shorted. Although the surge is short, there is
enough energy to damage parts of the IC.
10
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Device Functional Modes (continued)
When an output capacitor is connected to a regulator and the input is shorted, the output capacitor will discharge
into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage
of the regulator, and the rate of decrease of VIN. In the LM317L-N, this discharge path is through a large junction
that is able to sustain a 2-A surge with no problem. This is not true of other types of positive regulators. For
output capacitors of 25 μF or less, the ballast resistors and output structure of the LM317L-N limit the peak
current to a low enough level so that there is no need to use a protection diode.
The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs
when either the input or output is shorted. Internal to the LM317L-N is a 50-Ω resistor which limits the peak
discharge current. No protection is needed for output voltages of 25 V or less and 10-μF capacitance. Figure 15
shows an LM317L-N with protection diodes included for use with outputs greater than 25 V and high values of
output capacitance.
D1 protects against C1
D2 protects against C2
Figure 15. Regulator With Protection Diodes
7.4.3 DSBGA Light Sensitivity
Exposing the LM317L-N DSBGA package to bright sunlight may cause the VREF to drop. In a normal office
environment of fluorescent lighting the output is not affected. The LM317 DSBGA does not sustain permanent
damage from light exposure. Removing the light source causes VREF of the LM317L-N to recover to the proper
value.
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LM317L-N is a versatile, high-performance, linear regulator with 1% output-voltage accuracy. An output
capacitor can be added to further improve transient response, and the ADJ pin can be bypassed to achieve very
high ripple-rejection ratios. Its functionality can be used in many different applications that require high
performance regulation, such as battery chargers, constant-current regulators, and microprocessor supplies.
8.2 Typical Applications
8.2.1 1.25-V to 25-V Adjustable Regulator
Full output current not available at high input-output voltages
†Optional—improves transient response
*Needed if device is more than 6 inches from filter capacitors
Figure 16. 1.25-V to 25-V Adjustable Regulator
8.2.1.1 Design Requirements
The device component count is very minimal, employing two resistors as part of a voltage-divider circuit and an
output capacitor for load regulation. An input capacitor is needed if the device is more than 6 inches from filter
capacitors. An optional bypass capacitor across R2 can also be used to improve PSRR.
8.2.1.2 Detailed Design Procedure
The output voltage is set based on the selection of the two resistors, R1 and R2, as shown in Figure 16. For
details on capacitor selection, see External Capacitors.
12
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Typical Applications (continued)
8.2.1.3 Application Curve
As shown in Figure 17, VOUT rises with VIN minus some dropout voltage. This dropout voltage during start-up will
vary with ROUT.
VOUT = 5 V
Figure 17. VOUT vs VIN
8.2.2 Digitally-Selected Outputs
Figure 18 demonstrates a digitally-selectable output voltage. In its default state, all transistors are off and the
output voltage is set based on R1 and R2. By driving certain transistors, the associated resistor is connected in
parallel to R2, modifying the output voltage of the regulator.
*Sets maximum VOUT
Figure 18. Digitally-Selected Outputs
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Typical Applications (continued)
8.2.3 High Gain Amplifier
This application uses the LM395 Power Transistor to amplify the input voltage. The LM317L connected to R2
produces a constant current of 1.2V/R2 through the BJT. By altering the base current entering the LM395, the
effective resistance can be changed resulting in an appropriate voltage fluctuation at the output.
Figure 19. High Gain Amplifier
8.2.4 Adjustable Current Limiter
This application will limit the output current to the IOUT in the diagram. The current limit is determined by adjusting
the resistance between the VOUT and VADJ pins. The 1.2-V reference voltage across R1 generates the maximum
current.
12 ≤ R1 ≤ 240
Figure 20. Adjustable Current Limiter
8.2.5 Precision Current Limiter
This application will limit the output current to the IOUT in the diagram. An initial reference current is generated
based on the resistance between the VOUT and VADJ pins. In the case of Figure 21, 1.25 V across 1 kΩ plus half
of the 500-Ω resistor results in 1 mA of current, producing 1.5 V total across the two resistors in series. This
voltage also appears across R1, making the maximum current the sum of the branch currents.
Figure 21. Precision Current Limiter
14
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Typical Applications (continued)
8.2.6 Slow Turnon 15-V Regulator
An application of LM317L-N includes a PNP transistor with a capacitor to implement slow turnon functionality
(see Figure 22). As VIN rises, the PNP sinks current from the ADJ rail. The output voltage at start-up is the
addition of the 1.25-V reference plus the drop across the base to emitter. While this is happening, the capacitor
begins to charge and eventually opens the PNP. At this point, the device functions normally, regulating the
output at 15 V. A diode is placed between C1 and VOUT to provide a path for the capacitor to discharge. Such
controlled turnon is useful for limiting the in-rush current.
Figure 22. Slow Turnon 15-V Regulator
8.2.7 Adjustable Regulator With Improved Ripple Rejection
To improve ripple rejection, a capacitor is used to bypass the ADJ pin to GND (see Figure 23). This is used to
smooth output ripple by cleaning the feedback path and stopping unnecessary noise from being fed back into the
device, propagating the noise.
†Solid tantalum
*Discharges C1 if output is shorted to ground
Figure 23. Adjustable Regulator With Improved Ripple Rejection
8.2.8 High Stability 10-V Regulator
This application will regulate to an output voltage of 10 V and will remain stable even with input voltage
transients. The LM329 is a precision Zener reference diode that helps maintain stability.
Figure 24. High Stability 10-V Regulator
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Typical Applications (continued)
8.2.9 Adjustable Regulator With Current Limiter
This application regulates to an output voltage set by the ratio of R2 and R1 and limits the output current using
R3 as shown in Figure 25.
Short circuit current is approximately 600 mV/R3, or 60 mA (compared to LM317L-NZ's 200-mA current limit).
At 25-mA output only 3/4 V of drop occurs in R3 and R4.
Figure 25. Adjustable Regulator With Current Limiter
8.2.10 0-V to 30-V Regulator
This application regulates the output voltage from 0 V to 30 V using the resistor divider at the output. The
adjustment pin reference voltage is 1.25 V so select the resistor divider that provides the needed output voltage.
Full output current not available at high input-output voltages
Figure 26. 0-V to 30-V Regulator
16
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Typical Applications (continued)
8.2.11 Regulator With 15-mA Short-Circuit Current
This application regulates to a 10-V output with a 15-mA short-circuit current. The output voltage is set by the
resistor divider at the output and the PNP is required to set the short-circuit current.
Figure 27. Regulator With 15-mA Short-Circuit Current
8.2.12 Power Follower
This application provides an output voltage that follows the input voltage while providing a current gain. The
LM395 is a power transistor that operates as an emitter follower and provides a short-circuit current limit while
the LM317 acts as a constant-current load.
Figure 28. Power Follower
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Typical Applications (continued)
8.2.13 Adjusting Multiple On-Card Regulators With Single Control
Figure 29 shows how multiple LM317L-N regulators can be controlled by setting one resistor. Because each
device maintains the reference voltage of about 1.25 V between its VOUT and ADJ pins, we can connect each
ADJ rail to a single resistor, setting the same output voltage across all devices. This allows for independent
outputs, each responding to its corresponding input only. Designers must also consider that by the nature of the
circuit, changes to R1 and R2 will affect all regulators.
*All outputs within ± 100 mV
†Minimum load −5 mA
Figure 29. Adjusting Multiple On-Card Regulators With Single Control*
8.2.14 100-mA Current Regulator
This application regulates the output current to maximum of 100 mA as shown in Figure 30.
Figure 30. 100-mA Current Regulator
8.2.15 1.2-V to 12-V Regulator With Minimum Program Current
This application regulates the output voltage between 1.2 V and 12 V depending on the resistor divider at the
output while allowing minimum programmable load current down to 2 mA as shown in Figure 31.
*Minimum load current ≈ 2 mA
Figure 31. 1.2-V to 12-V Regulator With Minimum Program Current
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Typical Applications (continued)
8.2.16 50-mA Constant Current Battery Charger for Nickel-Cadmium Batteries
This application provides a 50-mA constant current at the output which can be used as a constant current battery
charger for Nickel-Cadmium batteries. The resistor at the output sets the output current value.
Figure 32. 50-mA Constant Current Battery Charger for Nickel-Cadmium Batteries
8.2.17 5-V Logic Regulator With Electronic Shutdown
Figure 33 shows a variation of the 5-V output regulator application uses the LM317L-N, along with an NPN
transistor, to provide shutdown control. The NPN will either block or sink the current from the ADJ pin by
responding to the TTL pin logic. When TTL is pulled high, the NPN is on and pulls the ADJ pin to GND, and the
LM317L-N outputs about 1.25 V. When TTL is pulled low, the NPN is off and the regulator outputs according to
the programmed adjustable voltage.
*Minimum output ≈ 1.2 V
Figure 33. 5-V Logic Regulator With Electronic Shutdown*
8.2.18 Current-Limited 6-V Charger
The current in a battery charger application is limited by switching between constant-current and constant-voltage
states (see Figure 34). When the battery pulls low current, the drop across the 1-Ω resistor is not substantial and
the NPN remains off. A constant voltage is seen across the battery, as regulated by the resistor divider. When
current through the battery rises past peak current, the 1 Ω provides enough voltage to turn the transistor on,
pulling ADJ close to ground. This results in limiting the maximum current to the battery.
*Sets peak current, IPEAK = 0.6 V/R1
**1000 μF is recommended to filter out any input transients.
Figure 34. Current Limited 6-V Charger
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Typical Applications (continued)
8.2.19 Short Circuit-Protected 80-V Supply
This application provides a 80-V output voltage from 0 mA to 20 mA as shown in Figure 35. The Triad provides
an AC to DC conversion and the short-circuit protection is provided by the fuse. The output voltage can be
adjusted by adjusting the resistor divider at the output.
Figure 35. Short Circuit-Protected 80-V Supply
20
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Typical Applications (continued)
8.2.20 Basic High-Voltage Regulator
This application regulates the output voltage from 1.2 V to 160 V at 25 mA as shown in Figure 36. The output
voltage is set by the resistor divider at the output. The Darlington pair transistor configuration provides a current
gain from the input source to the LM317.
Q1, Q2: NSD134 or similar
C1, C2: 1 μF, 200-V mylar**
*Heat sink
Figure 36. Basic High-Voltage Regulator
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Typical Applications (continued)
8.2.21 Precision High-Voltage Regulator
This application regulates the output voltage from 8 V to 160 V at 25 mA as shown in Figure 37. The Zener diode
connected from the adjust pin to VOUT provides better precision than the basic high-voltage regulator.
Q1, Q2: NSD134 or similar
C1, C2: 1 μF, 200-V mylar**
*Heat sink
**Mylar is a registered trademark of DuPont Co.
Figure 37. Precision High-Voltage Regulator
8.2.22 Tracking Regulator
This application regulates to an output voltage set by the output resistor divider and also uses the LM301A
operational amplifier to provide a negative voltage that tracks the output voltage.
A1 = LM301A, LM307, or LF13741 only
R1, R2 = matched resistors with good TC tracking
Figure 38. Tracking Regulator
22
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Typical Applications (continued)
8.2.23 Regulator With Trimmable Output Voltage
This application provides an output voltage set by the output resistor divider that can be finely tuned to ±1% by
removing output resistors. See the trim procedure in Figure 39.
Trim Procedure:
— If VOUT is 23.08 V or higher, cut out R3 (if lower, don't cut it out).
— Then if VOUT is 22.47 V or higher, cut out R4 (if lower, don't).
— Then if VOUT is 22.16 V or higher, cut out R5 (if lower, don't).
This will trim the output to well within ±1% of 22.00 VDC, without any of the expense or uncertainty of a trim pot (see
LB-46). This technique can be used at any output voltage level.
Figure 39. Regulator With Trimmable Output Voltage
8.2.24 Precision Reference With Short-Circuit Proof Output
This application provides a precise output voltage with short-circuit protection. The precision results from using
the LM308A operational amplifier connected between the adjust pin and output voltage pin as a comparator with
the LM299AH precision reference.
*R1–R4 from thin-film network,
Beckman 694-3-R2K-D or similar
Figure 40. Precision Reference With Short-Circuit Proof Output
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Typical Applications (continued)
8.2.25 Fully-Protected (Bulletproof) Lamp Driver
This application drives a lamp using a programmable gain instrumentation amplifier at the output.
Figure 41. Fully-Protected (Bulletproof) Lamp Driver
8.2.26 Lamp Flasher
This application uses a combination of capacitors and resistors connected between the output voltage pin and
the adjust pin to cause the lamp connected at the output voltage pin to flash.
Output rate—4 flashes per second at 10% duty cycle
Figure 42. Lamp Flasher
24
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9 Power Supply Recommendations
The input supply to the LM317L-N must be kept at a voltage level lower than the maximum input-to-output
differential voltage of 40 V. When possible, the minimum dropout voltage must also be met with extra headroom
to keep the LM317L-N in regulation. TI recommends using an input capacitor, especially when the input pin is
located more than 6 inches away from the power supply source. For more information regarding capacitor
selection, see External Capacitors.
10 Layout
10.1 Layout Guidelines
Some layout guidelines should be followed to ensure proper regulation of the output voltage with minimum noise.
Traces carrying the load current must be wide to reduce the amount of parasitic trace inductance and the
feedback loop from VOUT to ADJ should be kept as short as possible. To improve PSRR, a bypass capacitor can
be placed at the ADJ pin and must be located as close as possible to the IC. In cases when VIN shorts to ground,
an external diode should be placed from VOUT to VIN to divert the surge current from the output capacitor and
protect the IC. Similarly, in cases when a large bypass capacitor is placed at the ADJ pin and VOUT shorts to
ground, an external diode should be placed from ADJ to VOUT to provide a path for the bypass capacitor to
discharge. These diodes must be placed close to the corresponding IC pins to increase their effectiveness.
10.2 Layout Examples
Figure 43. Layout Example (SOT-223)
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Layout Examples (continued)
Figure 44. Layout Example (TO-220)
10.3 Thermal Considerations
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 VOUT, per watt, within the first 10 ms after a step of power is applied. The LM317L-N
specification is 0.2%/W, maximum.
In Figure 12, a typical output of the LM317L-N changes only 7 mV (or 0.07% of VOUT = −10 V) when a 1-W pulse
is applied for 10 ms. This performance is thus well inside the specification limit of 0.2%/W × 1 W = 0.2%
maximum. When the 1-W pulse is ended, the thermal regulation again shows a 7-mV change as the gradients
across the LM317L-N chip die out.
NOTE
The load regulation error of about 14 mV (0.14%) is additional to the thermal regulation
error.
26
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
For related documentation, see the following:
AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009)
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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18-Aug-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
LM317LITP/NOPB
ACTIVE
DSBGA
YPB
6
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 125
P
1
Samples
LM317LITPX/NOPB
ACTIVE
DSBGA
YPB
6
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 125
P
1
Samples
LM317LM/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
Call TI | SN
Level-1-260C-UNLIM
-40 to 125
LM317
LM
Samples
LM317LMX
NRND
SOIC
D
8
2500
Non-RoHS
& Green
Call TI
Level-1-235C-UNLIM
-40 to 125
LM317
LM
LM317LMX/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
Call TI | SN
Level-1-260C-UNLIM
-40 to 125
LM317
LM
Samples
LM317LZ/LFT1
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
LM317LZ/LFT2
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
LM317LZ/LFT3
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
LM317LZ/LFT4
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
LM317LZ/LFT7
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
LM317LZ/NOPB
ACTIVE
TO-92
LP
3
1800
RoHS & Green
SN
N / A for Pkg Type
LM317
LZ
Samples
-40 to 125
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
18-Aug-2022
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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