SBOS956 December   2018 INA240-SEP

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Typical Application
      2.      Enhanced PWM Rejection
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin 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
    6. 6.6 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Amplifier Input Signal
        1. 7.3.1.1 Enhanced PWM Rejection Operation
        2. 7.3.1.2 Input Signal Bandwidth
      2. 7.3.2 Selecting the Sense Resistor (RSENSE)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Adjusting the Output Midpoint 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 Midsupply 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 Calculating Total Error
        1. 7.4.4.1 Error Sources
        2. 7.4.4.2 Reference Voltage Rejection Ratio Error
          1. 7.4.4.2.1 Total Error Example 1
          2. 7.4.4.2.2 Total Error Example 2
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Input Filtering
    2. 8.2 Typical Applications
      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
      2. 8.2.2 Solenoid Drive Current-Sense Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
    3. 8.3 Do's and Don'ts
      1. 8.3.1 High-Precision Applications
      2. 8.3.2 Kelvin Connection from the Current-Sense Resistor
  9. Power Supply Recommendations
    1. 9.1 Power Supply Decoupling
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Connection to the Current-Sense Resistor
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

Detailed Design Procedure

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

To demonstrate the performance of the device, the INA240-SEP with a gain of 20 V/V was selected for this design and powered from a 5-V supply.

Using the information in the Adjusting the Output Midpoint With the Reference Pins 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-SEP is not saturated. A value of 100-mΩ was selected to maintain the analog input within the device limits.