SLYS041A March   2020  – March 2021 INA381-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Wide Input Common-Mode Voltage Range
      2. 7.3.2 Precise Low-Side Current Sensing
      3. 7.3.3 High Bandwidth and Slew Rate
      4. 7.3.4 Alert Output
      5. 7.3.5 Adjustable Overcurrent Threshold
      6. 7.3.6 Comparator Hysteresis
    4. 7.4 Device Functional Modes
      1. 7.4.1 Alert Modes
        1. 7.4.1.1 Transparent Output Mode
        2. 7.4.1.2 Latch Output Mode
  8. 8 Applications and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Select a Current-Sensing Resistor
        1. 8.1.1.1 Select a Current-Sensing Resistor: Example
      2. 8.1.2 Increase Comparator Hysteresis
      3. 8.1.3 Operation With Common-Mode Transients Greater Than 26 V
      4. 8.1.4 Input Filtering
    2. 8.2 Typical Applications
      1. 8.2.1 Bidirectional Window Comparator
        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 Low-Side Current Sensing
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.2 Precise Low-Side Current Sensing

When used in low-side current-sensing applications, the offset voltage of the INA381-Q1 is less than 150 µV. The low offset performance of the device has several benefits. First, the low offset allows the device to be used in applications that must measure current over a wide dynamic range. In this case, the low offset voltage improves accuracy when the sense currents are on the low end of the measurement range. Another advantage of low offset voltage is the ability to sense lower voltage drops across the sense resistor accurately, thus allowing for a lower-value shunt resistor. Lower-value shunt resistors reduce power loss in the current-sense circuit, and help improve the power efficiency of the end application.

The gain error of the INA381-Q1 is specified to be within 1% of the actual value. As the sensed voltage becomes much larger than the offset voltage, this gain error becomes the dominant source of error in the current-sense measurement.