LM317A

ACTIVE

1.5-A, 40-V, adjustable linear voltage regulator with high-accuracy

Product details

Output options Adjustable Output, Fixed Output Iout (max) (A) 1.5 Vin (max) (V) 40 Vin (min) (V) 3 Vout (max) (V) 37 Vout (min) (V) 1.2 Fixed output options (V) 37 Noise (µVrms) 38 Iq (typ) (mA) 5 Thermal resistance θJA (°C/W) 24 Rating Catalog, Military Load capacitance (min) (µF) 0 Regulated outputs (#) 1 Accuracy (%) 5 PSRR at 100 KHz (dB) 40 Dropout voltage (Vdo) (typ) (mV) 2250 Operating temperature range (°C) -40 to 125
Output options Adjustable Output, Fixed Output Iout (max) (A) 1.5 Vin (max) (V) 40 Vin (min) (V) 3 Vout (max) (V) 37 Vout (min) (V) 1.2 Fixed output options (V) 37 Noise (µVrms) 38 Iq (typ) (mA) 5 Thermal resistance θJA (°C/W) 24 Rating Catalog, Military Load capacitance (min) (µF) 0 Regulated outputs (#) 1 Accuracy (%) 5 PSRR at 100 KHz (dB) 40 Dropout voltage (Vdo) (typ) (mV) 2250 Operating temperature range (°C) -40 to 125
SOT-223 (DCY) 4 45.5 mm² 6.5 x 7 TO-220 (NDE) 3 46.5328 mm² 10.16 x 4.58 TO-252 (NDP) 3 65.2078 mm² 6.58 x 9.91 TO-CAN (NDT) 3 91.6742 mm² 10.03 x 9.14
  • For a newer drop-in alternative, see the LM317
  • Typical 0.005%/V line regulation
  • 1% output voltage tolerance
  • 1.5-A output current
  • Adjustable output down to 1.25 V
  • Input-output differential up to 40 V
  • Current limit constant with temperature
  • No output capacitor required
  • Short-circuit protected output
  • −40°C to 125°C operating temperature range
  • For a newer drop-in alternative, see the LM317
  • Typical 0.005%/V line regulation
  • 1% output voltage tolerance
  • 1.5-A output current
  • Adjustable output down to 1.25 V
  • Input-output differential up to 40 V
  • Current limit constant with temperature
  • No output capacitor required
  • Short-circuit protected output
  • −40°C to 125°C operating temperature range

The LM317A adjustable 3-terminal, positive-voltage regulators are capable of supplying current in excess of 1.5 A over a 1.25-V to 37-V output range and provide 1% output-voltage accuracy. Both line regulation and load regulation are better achieved with the LM317A device than with standard fixed regulators.

The LM317A offers full overload protection such as over current, thermal-overload protection, and safe-area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected.

Typically, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors, in which case an input bypass is needed. An optional output capacitor can be added to improve transient response and can be replaced with a ceramic and appropriate ESR. The adjustment terminal can be bypassed to achieve very high ripple-rejection ratios that are difficult to achieve with standard 3-terminal regulators.

Because the LM317A regulator is floating and detects 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. Exceeding the maximum input-to-output deferential will result in short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM317A can be also used as a precision current regulator.

For applications requiring greater output current, see the LM150 series (3A) and LM138 series (5A) data sheets. For the negative complement, see the LM137 series data sheet.

The LM317A adjustable 3-terminal, positive-voltage regulators are capable of supplying current in excess of 1.5 A over a 1.25-V to 37-V output range and provide 1% output-voltage accuracy. Both line regulation and load regulation are better achieved with the LM317A device than with standard fixed regulators.

The LM317A offers full overload protection such as over current, thermal-overload protection, and safe-area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected.

Typically, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors, in which case an input bypass is needed. An optional output capacitor can be added to improve transient response and can be replaced with a ceramic and appropriate ESR. The adjustment terminal can be bypassed to achieve very high ripple-rejection ratios that are difficult to achieve with standard 3-terminal regulators.

Because the LM317A regulator is floating and detects 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. Exceeding the maximum input-to-output deferential will result in short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM317A can be also used as a precision current regulator.

For applications requiring greater output current, see the LM150 series (3A) and LM138 series (5A) data sheets. For the negative complement, see the LM137 series data sheet.

Download View video with transcript Video

Similar products you might be interested in

open-in-new Compare alternates
Pin-for-pin with same functionality to the compared device
LM317 ACTIVE 1.5-A, 40-V, adjustable linear voltage regulator Pin-to-pin option for cost-sensitive applications
LM317HV ACTIVE 1.5-A, 60-V, adjustable linear voltage regulator Pin-to-pin equivalent which supports 60-V VIN
Same functionality with different pin-out to the compared device
LM1086 ACTIVE 1.5-A, 29-V, linear voltage regulator This product is a lower dropout (500mV), 1-A LDO regulator.

Technical documentation

star =Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 16
Type Title Date
* Data sheet LM317A 1% Accurate 1.5A Adjustable Voltage Regulator datasheet (Rev. A) PDF | HTML 09 Jun 2020
Application note A Topical Index of TI LDO Application Notes (Rev. F) 27 Jun 2019
EVM User's guide LM317A-337N-EVM User's Guide 21 Jan 2016
Technical article Create a simple LED driver PDF | HTML 20 Oct 2015
Technical article Overview of voltage regulator packaging PDF | HTML 27 Aug 2015
Technical article Identify the most accurate linear voltage regulator PDF | HTML 22 Aug 2015
Application note AN-1028 Maximum Power Enhancement Techniques for Power Packages (Rev. B) 06 May 2013
Application note AN-103 LM340 Series Three Terminal Positive Regulators (Rev. A) 06 May 2013
Application note AN-1148 Linear Regulators: Theory of Operation and Compensation (Rev. B) 06 May 2013
Application note AN-182 Improving Power Supply Reliability with IC Power Regulators (Rev. B) 05 May 2013
Application note Method For Cal Output Voltage Tolerances in Adj Regs (Rev. A) 05 May 2013
More literature Die D/S LM317A MWC 3-Terminal Adj Regulator 20 Sep 2012
Application note Packaging Limits Range of Linear Regulators 08 May 2010
Application note Digital Designer's Guide to Linear Voltage Regulators & Thermal Mgmt (LDO) (Rev. A) 04 Jun 2008
Application note Adjustable 3-Terminal Regulator for Low-Cost Battery Charging Systems 03 Oct 2002
Application note Understanding the Terms and Definitions of LDO Voltage Regulators 21 Oct 1999

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM317A-337N-EVM — 3-pin adjustable regulator evaluation module

The LM317A-337N-EVM demonstrates canonical application of the LM317A adjustable regulator and its negative complement, the LM337-N. The evaluation module (EVM) is assesmbled with the SOT-223 package option for each device, supplying up to 1 A of load current. The EVM is designed for easy (...)

User guide: PDF
Not available on TI.com
Simulation model

LM317A PSpice Transient Model (Rev. A)

SNVMAP0A.ZIP (54 KB) - PSpice Model
Simulation model

LM317A Unencrypted PSpice Transient Model (Rev. A)

SNVMAP1A.ZIP (2 KB) - PSpice Model
Package Pins CAD symbols, footprints & 3D models
SOT-223 (DCY) 4 Ultra Librarian
TO-220 (NDE) 3 Ultra Librarian
TO-252 (NDP) 3 Ultra Librarian
TO-CAN (NDT) 3 Ultra Librarian

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos