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Product details

Parameters

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 Load capacitance (Min) (µF) 0 Rating Catalog, Military Regulated outputs (#) 1 Features Accuracy (%) 5 PSRR @ 100 KHz (dB) 40 Dropout voltage (Vdo) (Typ) (mV) 2250 Operating temperature range (C) -40 to 125 open-in-new Find other Linear & low-dropout (LDO) regulators

Package | Pins | Size

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 open-in-new Find other Linear & low-dropout (LDO) regulators

Features

  • 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
open-in-new Find other Linear & low-dropout (LDO) regulators

Description

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) Jun. 09, 2020
Application note A Topical Index of TI LDO Application Notes (Rev. F) Jun. 27, 2019
User guide LM317A-337N-EVM User's Guide Jan. 21, 2016
Technical article Create a simple LED driver Oct. 20, 2015
Technical article Overview of voltage regulator packaging Aug. 27, 2015
Technical article Identify the most accurate linear voltage regulator Aug. 22, 2015
Application note AN-1028 Maximum Power Enhancement Techniques for Power Packages (Rev. B) May 06, 2013
Application note AN-103 LM340 Series Three Terminal Positive Regulators (Rev. A) May 06, 2013
Application note AN-1148 Linear Regulators: Theory of Operation and Compensation (Rev. B) May 06, 2013
Application note AN-182 Improving Power Supply Reliability with IC Power Regulators (Rev. B) May 05, 2013
Application note Method For Cal Output Voltage Tolerances in Adj Regs (Rev. A) May 05, 2013
More literature Die D/S LM317A MWC 3-Terminal Adj Regulator Sep. 20, 2012
Application note Packaging Limits Range of Linear Regulators May 08, 2010
Application note Digital Designer's Guide to Linear Voltage Regulators & Thermal Mgmt (LDO) (Rev. A) Jun. 04, 2008
Application note Adjustable 3-Terminal Regulator for Low-Cost Battery Charging Systems Oct. 03, 2002
Application note Understanding the Terms and Definitions of LDO Voltage Regulators Oct. 21, 1999

Design & development

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

Hardware development

EVALUATION BOARD Download
document-generic User guide
29
Description

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 (...)

Features
  • Output adjustable from 1.2 V to 37 V for LM317A and –1.2 V to –37 V for LM337-N
  • 1-A load current with 1.5-A option
  • Heat sink space provided for TO-220
  • Large capacitor footprint space for customer selection

Design tools & simulation

SIMULATION MODEL Download
SNVMAP0A.ZIP (54 KB) - PSpice Model
SIMULATION MODEL Download
SNVMAP1A.ZIP (2 KB) - PSpice Model

CAD/CAE symbols

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

Ordering & quality

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  • Ongoing reliability monitoring

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