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 Noise (uVrms) 38 Iq (Typ) (mA) 5 Thermal resistance θJA (°C/W) 24 Rating Catalog, Military Load capacitance (Min) (µF) 0 Regulated outputs (#) 1 Features Accuracy (%) 5 PSRR @ 100 KHz (dB) 40 Dropout voltage (Vdo) (Typ) (mV) 2250 Operating temperature range (C) -40 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 Noise (uVrms) 38 Iq (Typ) (mA) 5 Thermal resistance θJA (°C/W) 24 Rating Catalog, Military Load capacitance (Min) (µF) 0 Regulated outputs (#) 1 Features Accuracy (%) 5 PSRR @ 100 KHz (dB) 40 Dropout voltage (Vdo) (Typ) (mV) 2250 Operating temperature range (C) -40 to 125
SOT-223 (DCY) 4 46 mm² 6.5 x 7 TO-220 (NDE) 3 47 mm² 10.16 x 4.58 TO-252 (NDP) 3 40 mm² 7.3 x 6.58 TO-CAN (NDT) 3 92 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.

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Technical documentation

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Type Title Date
* Data sheet LM317A 1% Accurate 1.5A Adjustable Voltage Regulator datasheet (Rev. A) 09 Jun 2020
Technical article 3 quiescent-current (Iq) specifications you need to understand 12 Nov 2021
Application note A Topical Index of TI LDO Application Notes (Rev. F) 27 Jun 2019
User guide LM317A-337N-EVM User's Guide 21 Jan 2016
Technical article Create a simple LED driver 20 Oct 2015
Technical article Overview of voltage regulator packaging 27 Aug 2015
Technical article Identify the most accurate linear voltage regulator 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

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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 (...)

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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 Download
SOT-223 (DCY) 4 View options
TO (NDT) 3 View options
TO-220 (NDE) 3 View options
TO-252 (NDP) 3 View options

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