SLVS075J April   1989  – January 2015 LM285-1.2 , LM385-1.2 , LM385B-1.2

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  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 Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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発注情報

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

The The LM285-1.2, LM385-1.2, and LM385-1.2 devices create a voltage reference for to be used for a variety of applications including amplifiers, power supplies, and current-sensing circuits. The following application shows how to use these devices to establish a voltage reference.

9.2 Typical Application

lmx85app.gifFigure 8. Generating Reference Voltage with a Resistive Current Source

9.2.1 Design Requirements

The key design requirement when using this device as a voltage reference is to supply the LM385 with a minimum Cathode Current (IZ), as indicated in Electrical Characteristics.

9.2.2 Detailed Design Procedure

In order to generate a constant and stable reference voltage, a current greater than IZ(MIN) must be sourced into the cathode of this device. This can be accomplished using a current regulating device such as LM334 or a simple resistor. For a resistor, its value should be equal to or greater than (Vsupply - Vreference) ÷ IZ(MIN) .

9.2.3 Application Curves

tc8_slvs075.gifFigure 9. Transient Response

9.3 System Examples

Thermocouple Cold-Junction Compensator

app_slvs075.gifFigure 10. Thermocouple Cold-Junction Compensator

Generating Reference Voltage with a Constant Current Source

ap2_slvs075.gifFigure 11. Generating Reference Voltage with a Constant Current Source Device