LM317-N

ACTIVE

1.5-A, 40-V, adjustable linear voltage regulator

Product details

Output options Adjustable Output Iout (max) (A) 1.5 Vin (max) (V) 40 Vin (min) (V) 3 Vout (max) (V) 37 Vout (min) (V) 1.2 Rating Catalog, Military Noise (µVrms) 35 PSRR at 100 KHz (dB) 40 Iq (typ) (mA) 5 Thermal resistance θJA (°C/W) 39 Load capacitance (min) (µF) 0 Regulated outputs (#) 1 Accuracy (%) 5 Dropout voltage (Vdo) (typ) (mV) 2250 Operating temperature range (°C) 0 to 125
Output options Adjustable Output Iout (max) (A) 1.5 Vin (max) (V) 40 Vin (min) (V) 3 Vout (max) (V) 37 Vout (min) (V) 1.2 Rating Catalog, Military Noise (µVrms) 35 PSRR at 100 KHz (dB) 40 Iq (typ) (mA) 5 Thermal resistance θJA (°C/W) 39 Load capacitance (min) (µF) 0 Regulated outputs (#) 1 Accuracy (%) 5 Dropout voltage (Vdo) (typ) (mV) 2250 Operating temperature range (°C) 0 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-220 (NDG) 3 193.548 mm² 10.16 x 19.05 TO-252 (NDP) 3 65.2078 mm² 6.58 x 9.91 TO-263 (KTT) 3 154.8384 mm² 10.16 x 15.24 TO-CAN (NDT) 3 91.6742 mm² 10.03 x 9.14
  • For a newer drop-in alternative, see the LM317
  • Typ. 0.1% load regulation
  • Typ. 0.01%/V line regulation
  • 1.5-A output current
  • Adjustable output down to 1.25 V
  • Current limit constant with temperature
  • 80-dB ripple rejection
  • Short-circuit protected output
  • −55°C to 150°C operating temperature range (LM117)
  • For a newer drop-in alternative, see the LM317
  • Typ. 0.1% load regulation
  • Typ. 0.01%/V line regulation
  • 1.5-A output current
  • Adjustable output down to 1.25 V
  • Current limit constant with temperature
  • 80-dB ripple rejection
  • Short-circuit protected output
  • −55°C to 150°C operating temperature range (LM117)

The LM117 and LM317-N series of adjustable 3-pin positive voltage regulators are capable of supplying in excess of 1.5 A over a 1.25-V to 37-V output range and a wide temperature 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.

The LM117 and LM317-N offer full overload protection such as current limit, 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. 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 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. That is, avoid short-circuiting the output.

By connecting a fixed resistor between the adjustment pin and output, the LM117 and LM317-N can be also 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 1.25 V where most loads draw little current.

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

The LM117 and LM317-N series of adjustable 3-pin positive voltage regulators are capable of supplying in excess of 1.5 A over a 1.25-V to 37-V output range and a wide temperature 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.

The LM117 and LM317-N offer full overload protection such as current limit, 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. 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 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. That is, avoid short-circuiting the output.

By connecting a fixed resistor between the adjustment pin and output, the LM117 and LM317-N can be also 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 1.25 V where most loads draw little current.

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

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Technical documentation

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Type Title Date
* Data sheet LM117, LM317-N Wide Temperature Three-Pin Adjustable Regulator datasheet (Rev. Q) PDF | HTML 10 Jun 2020
Application note A Topical Index of TI LDO Application Notes (Rev. F) 27 Jun 2019
Selection guide Low Dropout Regulators Quick Reference Guide (Rev. P) 21 Mar 2018
Technical article Create a simple LED driver PDF | HTML 20 Oct 2015
Technical article Overview of voltage regulator packaging PDF | HTML 27 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
User guide AN-1164 LM3647 Reference Design User's Manual (Rev. B) 06 May 2013
Application note Method For Cal Output Voltage Tolerances in Adj Regs (Rev. A) 05 May 2013
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
User guide A User's Guide to Compensating Low-Dropout Regulators 21 Mar 2007
Application note Linear and Switching Voltage Regulator Fundamental Part 1 21 Mar 2007
Application note LB-46 A New Production Technique for Trimming Voltage Regulators 15 May 2004
Application note A New Production Technique for Trimming Voltage Regulators 03 Oct 2002
Application note Adjustable 3-Terminal Regulator for Low-Cost Battery Charging Systems 03 Oct 2002
Application note High Voltage Adjustable Power Supplies 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
Evaluation board

MLTLDO2EVM-037 — Universal LDO linear voltage regulator evaluation module for DCY, DDA and KVU packages

The MLTLDO2EVM-037 multipackage low-dropout (LDO) evaluation module (EVM) allows design engineers to evaluate the operation and performance of several common packages of linear regulators for possible use in their own circuit application. This EVM configuration contains a DDA, 3-pin and 5-pin KVU, (...)

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

LM317-N PSpice Transient Model

SNVMAP3.ZIP (52 KB) - PSpice Model
Simulation model

LM317-N Unencrypted PSpice Transient Model

SNVMAP2.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-220 (NDG) 3 Ultra Librarian
TO-252 (NDP) 3 Ultra Librarian
TO-263 (KTT) 3 Ultra Librarian
TO-CAN (NDT) 3 Ultra Librarian

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