SBOS808E August   2016  ā€“ December 2021 INA240-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  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
      1. 8.3.1 Amplifier Input Signal
        1. 8.3.1.1 Enhanced PWM Rejection Operation
        2. 8.3.1.2 Input Signal Bandwidth
      2. 8.3.2 Selecting the Sense Resistor (RSENSE)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Adjusting the Output Midpoint With the Reference Pins
      2. 8.4.2 Reference Pin Connections for Unidirectional Current Measurements
        1. 8.4.2.1 Ground Referenced Output
        2. 8.4.2.2 VS Referenced Output
      3. 8.4.3 Reference Pin Connections for Bidirectional Current Measurements
        1. 8.4.3.1 Output Set to External Reference Voltage
        2. 8.4.3.2 Output Set to Midsupply Voltage
        3. 8.4.3.3 Output Set to Mid-External Reference
        4. 8.4.3.4 Output Set Using Resistor Divider
      4. 8.4.4 Calculating Total Error
        1. 8.4.4.1 Error Sources
        2. 8.4.4.2 Reference Voltage Rejection Ratio Error
          1. 8.4.4.2.1 Total Error Example 1
          2. 8.4.4.2.2 Total Error Example 2
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Input Filtering
    2. 9.2 Typical Applications
      1. 9.2.1 Inline Motor Current-Sense Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Solenoid Drive Current-Sense Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
    3. 9.3 What to Do and What Not to Do
      1. 9.3.1 High-Precision Applications
      2. 9.3.2 Kelvin Connection from the Current-Sense Resistor
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Decoupling
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Connection to the Current-Sense Resistor
    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

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.1.2 Detailed Design Procedure

For this application, the INA240-Q1 measures current in the drive circuitry of a 36-V, 4000-RPM motor.

To demonstrate the performance of the device, the INA240A1-Q1 with a gain of 20 V/V was selected for this design and powered from a 5-V supply.

Using the information in the Section 8.4.1 section, the reference point is set to midscale by splitting the supply with REF1 connected to ground and REF2 connected to supply. This configuration allows for bipolar current measurements. Alternatively, the reference pins can be tied together and driven with an external precision reference.

The current-sensing resistor is sized so that the output of the INA240-Q1 is not saturated. A value of 100-mĪ© was selected to maintain the analog input within the device limits.