SBOSAC3A July   2023  – December 2023 INA745A , INA745B

PRODMIX  

  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 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Device Measurement Range and Resolution
      2. 7.1.2 ADC Output Data Rate and Noise Performance
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Configure the Device
        2. 7.2.2.2 Set Desired Fault Thresholds
        3. 7.2.2.3 Calculate Returned Values
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
    5. 7.5 Register Maps
      1. 7.5.1 INA745x Registers
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.3 Versatile Measurement Capability

The INA745x operates off a 2.7 V to 5.5 V supply but can measure voltage and current on rails as high as 40 V. The current is measured by sensing the voltage drop across an internal shunt resistor. The input stage of the INA745x 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 –0.1 V to +40 V 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 vice-versa) 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 0 V to 40 V, 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).

GUID-20230530-SS0I-TPSM-PF1S-JF5PRW1NV1BF-low.svgFigure 6-6 High-Voltage Input Multiplexer