SBOS562G August   2011  – June 2020 INA826

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      General-Purpose Instrumentation Amplifier
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin 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
      1. 8.3.1  Inside the INA826
      2. 8.3.2  Setting the Gain
        1. 8.3.2.1 Gain Drift
      3. 8.3.3  Offset Trimming
      4. 8.3.4  Input Common-Mode Range
      5. 8.3.5  Input Protection
      6. 8.3.6  Input Bias Current Return Path
      7. 8.3.7  Reference Terminal
      8. 8.3.8  Dynamic Performance
      9. 8.3.9  Operating Voltage
        1. 8.3.9.1 Low-Voltage Operation
      10. 8.3.10 Error Sources
    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
      1. 9.3.1 Circuit Breaker
      2. 9.3.2 Programmable Logic Controller (PLC) Input
      3. 9.3.3 Using TINA-TI SPICE-Based Analog Simulation Program With the INA826
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 CMRR vs Frequency
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.2.1 Gain Drift

The stability and temperature drift of the external gain setting resistor, RG, also affects gain. The contribution of RG to gain accuracy and drift is directly inferred from the gain of Equation 1.

The best gain drift of 1 ppm/℃ is achieved when the INA826 uses G = 1 without RG connected. In this case, the gain drift is limited only by the slight mismatch of the temperature coefficient of the integrated 50-kΩ resistors in the differential amplifier (A3). At G greater than 1, the gain drift increases as a result of the individual drift of the 24.7-kΩ resistors in the feedback of A1 and A2, relative to the drift of the external gain resistor RG. Process improvements of the temperature coefficient of the feedback resistors now make possible specifying a maximum gain drift of the feedback resistors of 35 ppm/℃, thus significantly improving the overall temperature stability of applications using gains greater than 1.

Low resistor values required for high gain can make wiring resistance important. Sockets add to the wiring resistance and contribute additional gain error (such as a possible unstable gain error) at gains of approximately 100 or greater. To maintain stability, avoid parasitic capacitance of more than a few picofarads at RG connections. Careful matching of any parasitics on both RG pins maintains optimal CMRR over frequency; see Figure 19 and Figure 20.