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Shunt voltage references

LM431

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2%, 1%, or 0.5% accuracy, adjustable precision Zener shunt regulator

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Data sheet

LM431

ACTIVE
Data sheet Order now

Product details

VO (V) 2.5 Initial accuracy (max) (%) 0.5, 1, 2 VO adj (min) (V) 2.5 VO adj (max) (V) 36 Iz for regulation (min) (µA) 400 Reference voltage (V) adjustable Rating Catalog Temp coeff (max) (ppm/°C) 97 Operating temperature range (°C) -40 to 85 Iout/Iz (max) (mA) 100
VO (V) 2.5 Initial accuracy (max) (%) 0.5, 1, 2 VO adj (min) (V) 2.5 VO adj (max) (V) 36 Iz for regulation (min) (µA) 400 Reference voltage (V) adjustable Rating Catalog Temp coeff (max) (ppm/°C) 97 Operating temperature range (°C) -40 to 85 Iout/Iz (max) (mA) 100
SOIC (D) 8 29.4 mm² 4.9 x 6 SOT-23 (DBZ) 3 6.9204 mm² 2.92 x 2.37 TO-92 (LP) 3 19.136 mm² 5.2 x 3.68
  • Average Temperature Coefficient 50 ppm/°C
  • Temperature Compensated for Operation Over
    the Full Temperature Range
  • Programmable Output Voltage
  • Fast Turnon Response
  • Low-Output Noise
  • Low-Dynamic Output Impedance
  • Available in Space-Saving SOIC-8, SOT-23, and
    TO-92 Packages
  • Average Temperature Coefficient 50 ppm/°C
  • Temperature Compensated for Operation Over
    the Full Temperature Range
  • Programmable Output Voltage
  • Fast Turnon Response
  • Low-Output Noise
  • Low-Dynamic Output Impedance
  • Available in Space-Saving SOIC-8, SOT-23, and
    TO-92 Packages

The LM431 is a 3-terminal adjustable shunt regulator with ensured temperature stability over the entire temperature range of operation. The output voltage may be set at any level greater than 2.5 V (VREF) up to 36 V merely by selecting two external resistors that act as a voltage divided network. Due to the sharp turnon characteristics this device is an excellent replacement for many Zener diode applications.

The LM431 is available in space-saving SOIC-8, SOT-23, and TO-92 packages.

The LM431 is a 3-terminal adjustable shunt regulator with ensured temperature stability over the entire temperature range of operation. The output voltage may be set at any level greater than 2.5 V (VREF) up to 36 V merely by selecting two external resistors that act as a voltage divided network. Due to the sharp turnon characteristics this device is an excellent replacement for many Zener diode applications.

The LM431 is available in space-saving SOIC-8, SOT-23, and TO-92 packages.
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Technical documentation

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Type Title Date
* Data sheet LM431 Adjustable Precision Zener Shunt Regulator datasheet (Rev. H) PDF | HTML 06 Jan 2016
Application brief A Simple Constant Voltage Regulation Using the MODE Pin (Rev. A) PDF | HTML 15 Feb 2024
E-book Tips and tricks for designing with voltage references (Rev. A) 07 May 2021
Selection guide 431 Device Nomenclature (Rev. B) 18 Sep 2019
E-book Voltage Supervisor and Reset ICs: Tips, Tricks and Basics 28 Jun 2019
Analog Design Journal Low-cost flyback solutions for 10-mW standby power 22 Jan 2014
Application note AN-2102 LM3464 and LM5021 DHC 25W Reference Designs (Rev. A) 01 May 2013
Application note Precision Output Current Limiting Using Average Current Monitor Feature 21 Jun 2011
Application note TO-92 Packing Options / Ordering Instructions (Rev. A) 23 Jun 2010

Design & development

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

Evaluation board

ATL431EVM-001 — ATL431 adjustable shunt regulator evaluation module

The ATL431EVM-001 evaluation module (EVM) features the functionality and adjustability of the ATL431 by letting you program the cathode voltage with various resistor values. You can also set the cathode current using the various resistors in series with the supply. (...)

User guide: PDF
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Simulation model

LM431 Unencrypted PSpice Transient Model Package (Rev. A)

SNVMAB5A.ZIP (49 KB) - PSpice Model
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Calculation tool

SHUNT_VOLTAGE_REFERENCE_RESISTOR_CALCULATOR — Shunt Voltage Reference External Resistor Quick Start Calculator

This external resistor quick-start calculator tool lets you easily calculate valid external resistor values relative to voltage reference, supply and load-current bounds. With these inputs, you can instantly view the resulting calculations and use the color-coded indications to understand (...)

Supported products & hardware

Supported products & hardware

Products
Die & wafer services
LM336-2.5-MIL — Shunt Voltage Reference
Shunt voltage references
ATL431 — 2.5-V low-IQ adjustable precision shunt regulator LM136-2.5-N — Voltage Reference Diode LM136-5.0 — 5.0V Reference Diode LM136-5.0QML — 5.0V Reference Diode LM136A-2.5QML — 2.5V Reference Diode LM136A-2.5QML-SP — Radiation-hardened QMLV, 2.5-V shunt voltage reference LM136A-5.0QML — 5.0V Reference Diode LM185-1.2-N — Micropower Voltage Reference Diode LM185-1.2QML — Micropower Voltage Reference Diode LM185-1.2QML-SP — Radiation-hardened QMLV, 1.2-V shunt voltage reference LM185-2.5-N — Micropower Voltage Reference Diode LM185-2.5QML — Micropower Voltage Reference Diode LM185-2.5QML-SP — Space-grade QMLV 2.5-V  shunt voltage reference LM185-ADJ — Adjustable Micropower Voltage Reference LM185QML — Adjustable Micropower Voltage Reference LM285-1.2 — 1.235-V, –40°C to +85°C, micropower voltage reference LM285-1.2-N — 1.235-V, –40°C to +85°C, micropower voltage reference diode LM285-2.5 — 2.5-V, –40°C to +85°C, micropower voltage reference LM285-2.5-N — 2.5-V, –40°C to +85°C, micropower voltage reference diode LM285-ADJ — Adjustable, 85°C, micropower voltage reference LM336-2.5 — 0°C to 70°C, 2.5-V integrated reference circuit LM336-2.5-N — Voltage reference diode LM336-5.0 — 5-V reference diode LM385-1.2 — 1.235-V, 2%, 0°C to 70°C, micropower voltage reference LM385-1.2-MIL — Micropower Voltage Reference LM385-1.2-N — 1.235-V, 0°C to 70°C, micropower voltage reference diode LM385-2.5 — 2.5-V, 2%, 70°C, micropower voltage reference LM385-2.5-N — 2.5-V, 0°C to 70°C, micropower voltage reference diode LM385-ADJ — Adjustable, 70°C, micropower voltage reference LM4030 — Ultra-high-precision shunt voltage reference LM4040 — Fixed voltage, 45-µA, precision micropower shunt voltage reference LM4040-N — 100-ppm/°C precision micropower shunt voltage reference LM4040-N-Q1 — Automotive, 100-ppm/°C precision micropower shunt voltage reference LM4041-N — Fixed & adjustable, 45-µA, precision micropower shunt voltage reference LM4041-N-Q1 — Automotive, precision micropower shunt voltage reference LM4050-N — 50-ppm/°C precision micropower shunt voltage reference LM4050-N-Q1 — Automotive, 50-ppm/°C precision micropower shunt voltage reference LM4050QML-SP — Radiation-hardened QMLV, 2.5-V or 5-V shunt voltage reference LM4051-N — Fixed & adjustable, precision micropower shunt voltage reference LM431 — 2%, 1%, or 0.5% accuracy, adjustable precision Zener shunt regulator LM4431 — Micropower shunt voltage reference LMV431 — 1.5%, low-voltage (1.24-V) adjustable precision shunt regulator LMV431A — 1%, low-voltage (1.24-V) adjustable precision shunt regulator LMV431B — 0.5%, low-voltage (1.24-V) adjustable precision shunt regulator
Current references & sources
LM134 — 3-Terminal Adjustable Current Source LM234 — 100°C 3-pin adjustable current source LM334 — 0°C to 70°C 3-pin adjustable current source
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Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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Reference designs

PMP10723 — Isolated 53V/400mA Output Flyback Solution Reference Design Featuring the LM3481

PMP10723 is an isolated output flyback solution that accepts an input voltage of 9 VIN to 16 VIN and provides a 53-V/400-mA output. With secondary control, it can achieve great load regulation performance. Also it can fan out to cover other isolated high-voltage applications just by changing the (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP10725 — Multiport Isolated Output Flyback Solution Reference Design Featuring the LM3481

PMP10725 is an isolated flyback solution which accepts an input voltage of 15 to 36VIN and provides multiport output to the load. This reference design compares primary and secondary control solutions. With primary control, it can achieve higher efficiency with lower BOM cost, but the regulation (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP20396 — 400V Input, 50W Output Multiple-Output Bias Supply Reference Design

PMP20396 is a multiple-output isolated bias supply reference design. With 100V or above input voltage, this design can provide maximum 2W output power. With 300V or above input voltage, this design can provide maximum 50W output power. Four different outputs are provided in this design - 5V/500mA (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP10594 — 97% efficiency, 125W, Wide input Synchronous 4-Switch Buck-Boost Battery Charger Reference Design

PMP10594 is a synchronous 4-switch buck-boost converter reference design which utilizes the LM5175 controller for battery charger applications. The output voltage set point can be adjusted by a PWM signal over the range of 7.1V to 9.2V. I2C programming allows independent control of the (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP20001 — Flyback Reference Design with High Line AC Input and 5V, 12V Dual-Output

The PMP11405 reference design uses the UCC28740 constant current (CC), constant voltage (CV) flyback controller for a 5V/1A, 12V/0.9A bias supply with high line AC input (185VAC to 260VAC input). With safety isolated, Over 80% efficiency is achieved at full load and less than 400mW power (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP15012 — Inverting Buck-Boost Reference Design Featuring LMR16020 DC/DC Buck Converter

The PMP15012 reference design is a DC/DC buck-boost solution which accepts an input voltage of 18V to 36V and provides negative 15V/200mA output to the load. This reference design adds an external UVLO circuit to narrow the UVLO hysteresis because a buck-boost converter is difficult to shut down. (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP8920 — High-Eff 2Stage Univ Input Pwr Supply Using Trans Mode PFC/LLC Resonant Conv Reference Design

Low EMI, high efficiency, high power factor and reliable power supply are main focus of the PMP8920 design for telecom applications. Transient mode (TM) power factor correction (PFC) with UCC28051 and LLC series resonant converter (SRC) with UCC25600 are applied in PMP8911. In addition, (...)
Test report: PDF
Reference designs

PMP10680 — 4.5V to 24V Wide Input, Negative 5V/2A Output Non-synchronous Converter Reference Design

The PMP10680 reference design is a non-sync buck converter with buck-boost configuration. The PMP10680 accepts an input voltage of 4.5 to 24Vin and provides a negative 5V output capable of supplying continuous 2A of current to the load. With negative output and the self-positive input, (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP9739 — 250W Single Stage LLC-SRC Converter Reference Design

The PMP9739 is a single stage LLC series resonant converter (SRC), producing up to a 250W output using UCC25600 resonant controller. With the use of single stage LLC-SRC, the converter efficiency goes up to 89% at 250W full output power.
Test report: PDF
Schematic: PDF
Reference designs

PMP6024 — 100-240VAC Input, 60W, 2-string, PWM Dimmable LED Driver Reference Design

PMP6024 is an offline, LED driver circuit consisting of an isolated, power-factor corrected, constant output voltage flyback converter followed by two DC/DC buck LED current controllers.  It is suitable for indoor or outdoor area lighting applications of 3500-5000 lumens (depending upon LED (...)
Test report: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
SOIC (D) 8 Ultra Librarian
SOT-23 (DBZ) 3 Ultra Librarian
TO-92 (LP) 3 Ultra Librarian
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