SBOSA30D March   2022  – December 2024

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Amplifier Input Common-Mode Signal
        1. 7.3.1.1 Enhanced PWM Rejection Operation
        2. 7.3.1.2 Input-Signal Bandwidth
        3. 7.3.1.3 Low Input Bias Current
        4. 7.3.1.4 Low VSENSE Operation
        5. 7.3.1.5 Wide Fixed Gain Output
        6. 7.3.1.6 Wide Supply Range
    4. 7.4 Device Functional Modes
      1. 7.4.1 Adjusting the Output With the Reference Pins
      2. 7.4.2 Reference Pin Connections for Unidirectional Current Measurements
        1. 7.4.2.1 Ground Referenced Output
        2. 7.4.2.2 VS Referenced Output
      3. 7.4.3 Reference Pin Connections for Bidirectional Current Measurements
        1. 7.4.3.1 Output Set to External Reference Voltage
        2. 7.4.3.2 Output Set to Mid-Supply Voltage
        3. 7.4.3.3 Output Set to Mid-External Reference
        4. 7.4.3.4 Output Set Using Resistor Divider
      4. 7.4.4 High Signal Throughput
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 RSENSE and Device Gain Selection
    2. 8.2 Typical Application
      1. 8.2.1 Inline Motor Current-Sense Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power Supply Decoupling
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.1.2 Detailed Design Procedure

For this application, the INA241x measures current in the drive circuitry of a 48V, 4000 RPM motor.

To demonstrate the performance of the device, the INA241A2 with a gain of 20V/V is selected for this design and powered from a 5V supply.

Using the information in the Section 7.4.3.2 section, the reference point is set to mid-scale by splitting the supply with REF1 connected to supply and REF2 connected to ground. 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 INA241x is not saturated. A value of 100mΩ is selected to maintain the analog input within the device limits.