SBOSAK9A May   2025  – October 2025 INA745A-Q1 , INA745B-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 Timing Requirements (I2C)
    7. 5.7 Timing Diagram
    8. 5.8 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 Versatile Measurement Capability
      4. 6.3.4 Internal Measurement and Calculation Engine
      5. 6.3.5 High-Precision Delta-Sigma ADC
        1. 6.3.5.1 Low Latency Digital Filter
        2. 6.3.5.2 Flexible Conversion Times and Averaging
      6. 6.3.6 Integrated Precision Oscillator
      7. 6.3.7 Multi-Alert Monitoring and Fault Detection
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Power-On Reset
    5. 6.5 Programming
      1. 6.5.1 I2C Serial Interface
        1. 6.5.1.1 Writing to and Reading Through the I2C Serial Interface
        2. 6.5.1.2 High-Speed I2C Mode
        3. 6.5.1.3 SMBus Alert Response
  8. 7 Register Maps
    1. 7.1 INA745x-Q1 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Device Measurement Range and Resolution
      2. 8.1.2 ADC Output Data Rate and Noise Performance
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Configure the Device
        2. 8.2.2.2 Set Desired Fault Thresholds
        3. 8.2.2.3 Calculate Returned Values
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  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

6.3.3 Versatile Measurement Capability

The INA745x-Q1 operates off a 2.7V to 5.5V supply but can measure voltage and current on rails as high as 40V. The current is measured by sensing the voltage drop across an internal shunt resistor. The input stage of the INA745x-Q1 is designed such that the input common-mode voltage can be higher than the device supply voltage, VS. The common-mode voltage range at the inputs is –0.1V to 40V to support both high-side and low-side current measurements. There are no special considerations for power-supply sequencing because the common-mode input range and device supply voltage are independent of each other; therefore the bus voltage can be present with the supply voltage off (and reciprocally) without damaging the device.

The device also measures the bus supply voltage through the VBUS pin and temperature through the integrated temperature sensor. The current is calculated from the voltage drop across the internal shunt resistor which is sensed by the IN+ and IN– pins, while the bus voltage is measured with respect to device ground. Monitored bus voltages can range from 0V to 40V, while monitored temperatures can range from –40°C to 150°C.

Shunt voltage, bus voltage, and internal temperature measurements are multiplexed internally to a single ADC (see Figure 6-6).

INA745A-Q1 INA745B-Q1 High-Voltage Input Multiplexer Figure 6-6 High-Voltage Input Multiplexer