SLOS066W September   1975  – March 2015 LM124 , LM124A , LM224 , LM224A , LM224K , LM224KA , LM2902 , LM2902K , LM2902KAV , LM2902KV , LM324 , LM324A , LM324K , LM324KA

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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 for LMx24 and LM324K
    6. 6.6 Electrical Characteristics for LM2902 and LM2902V
    7. 6.7 Electrical Characteristics for LMx24A and LM324KA
    8. 6.8 Operating Conditions
    9. 6.9 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Unity-Gain Bandwidth
      2. 8.3.2 Slew Rate
      3. 8.3.3 Input Common Mode Range
    4. 8.4 Device Functional Modes
  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 Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 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 LMx24 and LM2902 operational amplifiers are useful in a wide range of signal conditioning applications. Inputs can be powered before VCC for flexibility in multiple supply circuits.

9.2 Typical Application

A typical application for an operational amplifier in an inverting amplifier. This amplifier takes a positive voltage on the input, and makes it a negative voltage of the same magnitude. In the same manner, it also makes negative voltages positive.

LM124 LM124A LM224 LM224A LM224K LM224KA LM324 LM324A LM324K LM324KA LM2902 LM2902V LM2902K LM2902KV LM2902KAV app_sch.gifFigure 9. Application Schematic

9.2.1 Design Requirements

The supply voltage must be chosen such that it is larger than the input voltage range and output range. For instance, this application will scale a signal of ±0.5 V to ±1.8 V. Setting the supply at ±12 V is sufficient to accommodate this application.

9.2.2 Detailed Design Procedure

Determine the gain required by the inverting amplifier using Equation 1 and Equation 2:

Equation 1. LM124 LM124A LM224 LM224A LM224K LM224KA LM324 LM324A LM324K LM324KA LM2902 LM2902V LM2902K LM2902KV LM2902KAV app_eq1.gif
Equation 2. LM124 LM124A LM224 LM224A LM224K LM224KA LM324 LM324A LM324K LM324KA LM2902 LM2902V LM2902K LM2902KV LM2902KAV app_eq2.gif

Once the desired gain is determined, choose a value for RI or RF. Choosing a value in the kilohm range is desirable because the amplifier circuit will use currents in the milliamp range. This ensures the part will not draw too much current. This example will choose 10 kΩ for RI which means 36 kΩ will be used for RF. This was determined by Equation 3.

Equation 3. LM124 LM124A LM224 LM224A LM224K LM224KA LM324 LM324A LM324K LM324KA LM2902 LM2902V LM2902K LM2902KV LM2902KAV app_eq3.gif

9.2.3 Application Curve

LM124 LM124A LM224 LM224A LM224K LM224KA LM324 LM324A LM324K LM324KA LM2902 LM2902V LM2902K LM2902KV LM2902KAV app_graph.gifFigure 10. Input and Output Voltages of the Inverting Amplifier