SBOSAD1 May   2024 INA791B

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Integrated Shunt Resistor
      2. 6.3.2 Safe Operating Area
      3. 6.3.3 Short-Circuit Duration
      4. 6.3.4 Temperature Stability
    4. 6.4 Device Functional Modes
      1. 6.4.1 Adjusting the Output With the Reference Pin
        1. 6.4.1.1 Reference Pin Connections for Unidirectional Current Measurements
        2. 6.4.1.2 Ground Referenced Output
        3. 6.4.1.3 Reference Pin Connections for Bidirectional Current Measurements
        4. 6.4.1.4 Output Set to Mid-Supply Voltage
      2. 6.4.2 Adjustable Gain Set Using External Resistors
        1. 6.4.2.1 Adjustable Unity Gain
      3. 6.4.3 Thermal Alert Function
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Calculating Total Error
        1. 7.1.1.1 Error Sources
        2. 7.1.1.2 Reference Voltage Rejection Ratio Error
        3. 7.1.1.3 External Adjustable Gain Error
        4. 7.1.1.4 Total Error Example 1
        5. 7.1.1.5 Total Error Example 2
        6. 7.1.1.6 Total Error Example 3
    2. 7.2 Typical Applications
      1. 7.2.1 High-Side, High-Drive, Solenoid Current-Sense Application
        1. 7.2.1.1 Design Requirements
  9. 8 Power Supply Recommendations
  10. 9 Layout Example
  11. 10Layout Guidelines
  12. 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
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

6.3.1 Integrated Shunt Resistor

The INA791x features an integrated EZShunt™ technology current-sensing resistor that provides accurate measurements over the entire specified temperature range of –40°C to +125°C. The integrated current-sensing resistor provides measurement stability over temperature, and simplifies printed circuit board (PCB) layout and board constraint difficulties common in high-precision measurements.

The onboard current-sensing resistor is designed as a 4-wire (or Kelvin) connected resistor that enables accurate measurements through a force-sense connection. Internally connected amplifier input pins (IN– and IN+) to the sense pins of the shunt resistor eliminates many instances of parasitic impedance commonly found in typical very-low sensing-resistor level measurements. The INA791x is system-calibrated to make sure that the current-sensing resistor and current-sensing amplifier are both precisely matched to one another. The in-package integrated sensing resistor must be used with the internal current-sensing amplifier to achieve the optimized system gain specification.

The INA791x has approximately 550µΩ of package resistance. Of this total package resistance, 400µΩ resistance from the Kelvin-connected current-sensing resistor is used by the amplifier. The power dissipation requirements of the system and package are based on the total 550µΩ package resistance between the IS+ and IS– pins.

INA791B IS+ to IS– Package Resistance vs Temperature Figure 6-1 IS+ to IS– Package Resistance vs Temperature