SNVS020H May   2000  – January 2016 LM431

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Shunt Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Other Applications
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Community Resources
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ

8 Detailed Description

8.1 Overview

The LM431 is an adjustable precision shunt voltage regulator with ensured temperature stability over the entire temperature range. The part has three different packages available to meet small footprint requirements, and is available in three different tolerance grades.

8.2 Functional Block Diagram

LM431 1005599.png
Figure 9. LM431 Symbol
LM431 1005555.png
Figure 10. LM431 Block Diagram

8.3 Feature Description

The LM431 is a precision Zener diode. The part requires a small quiescent current for regulation, and regulates the output voltage by shunting more or less current to ground, depending on input voltage and load. The only external component requirement is a resistor between the cathode and the input voltage to set the input current. An external capacitor can be used on the input or output, but is not required.

LM431 1005503.png Figure 11. Equivalent Circuit

8.4 Device Functional Modes

The LM431 is most commonly operated in closed-loop mode, where the reference node is tied to the output voltage via a resistor divider. The output voltage remains in regulation as long as Iz is between 1 mA and 100 mA. The part can also be used in open-loop mode to act as a comparator, driving the feedback node from another voltage source.