SBOSAE3 January   2026 INA790A-Q1 , INA790B-Q1

PRODUCTION DATA  

  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
    6. 5.6 Typical 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 Drift Correction
      5. 6.3.5 Enhanced PWM Rejection Operation
    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
        7. 7.1.1.7 Total Error Curves
      2. 7.1.2 Signal Filtering
    2. 7.2 Typical Applications
      1. 7.2.1 High-Side, High-Drive, Solenoid Current-Sense Application
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Speaker Enhancements and Diagnostics Using Current Sense Amplifier
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curve
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.2.2.2 Detailed Design Procedure

For this application, the INA790x-Q1 measures current flowing through the speaker from the CLASS-D amplifier. The integrated shunt of 400µΩ with an inductance of only 2nH is an excellent choice for current sensing in speaker applications where low inductance is required. The low-inductive shunt enables accurate current sensing across frequencies over the audio range of 20Hz to 20kHz.

The INA790x-Q1 is setup to support bidirectional currents with the reference set to mid-supply as shown in Output Set to Mid-Supply Voltage. When the power supply to the INA790x-Q1 is set at 3.3V and there is no current flowing in the speaker, the output of INA790x-Q1 is at 1.65V. When operating with a gain of 80mV/A with peak-to-peak current of ±15A, the output of the INA790x-Q1 swings from 0.45V to 2.85V. In this application the output can be directly connected to an ADC input that has a full scale range of 3.3V. The INA790x-Q1 can measure the impedance of the speaker and accurately measure the resonance frequency and peak impedance at resonance frequency. The INA790x-Q1 can accurately track changes in the impedance in real-time.