SBOSA20A February   2021  – May 2022 INA237

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 Timing Requirements (I2C)
    7. 6.7 Timing Diagram
    8. 6.8 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 Versatile High Voltage Measurement Capability
      2. 7.3.2 Power Calculation
      3. 7.3.3 Low Bias Current
      4. 7.3.4 High-Precision Delta-Sigma ADC
        1. 7.3.4.1 Low Latency Digital Filter
        2. 7.3.4.2 Flexible Conversion Times and Averaging
      5. 7.3.5 Integrated Precision Oscillator
      6. 7.3.6 Multi-Alert Monitoring and Fault Detection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Power-On Reset
    5. 7.5 Programming
      1. 7.5.1 I2C Serial Interface
        1. 7.5.1.1 Writing to and Reading Through the I2C Serial Interface
        2. 7.5.1.2 High-Speed I2C Mode
        3. 7.5.1.3 SMBus Alert Response
    6. 7.6 Register Maps
      1. 7.6.1 INA237 Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Device Measurement Range and Resolution
      2. 8.1.2 Current and Power Calculations
      3. 8.1.3 ADC Output Data Rate and Noise Performance
      4. 8.1.4 Input Filtering Considerations
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Select the Shunt Resistor
        2. 8.2.2.2 Configure the Device
        3. 8.2.2.3 Program the Shunt Calibration Register
        4. 8.2.2.4 Set Desired Fault Thresholds
        5. 8.2.2.5 Calculate Returned Values
      3. 8.2.3 Application Curves
  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 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.1.1 Device Measurement Range and Resolution

The INA237 device supports two input ranges for the shunt voltage measurement. The supported full scale differential input across the IN+ and IN– pins can be either ±163.84 mV or ±40.96 mV depending on the ADCRANGE bit in CONFIG register. The range for the bus voltage measurement is from 0 V to 85 V. The internal die temperature sensor range extends from –256 °C to +256 °C but is limited by the package to –40 °C to 125 °C.

Table 8-1 provides a description of full scale voltage on shunt, bus, and temperature measurements, along with their associated step size.

Table 8-1 ADC Full Scale Values
PARAMETERFULL SCALE VALUERESOLUTION
Shunt voltage±163.84 mV (ADCRANGE = 0) 5 µV/LSB
±40.96 mV (ADCRANGE = 1) 1.25 µV/LSB
Bus voltage0 V to 85 V3.125 mV/LSB
Temperature–40 °C to +125 °C 125 m°C/LSB

The device shunt voltage measurements, bus voltage, and temperature measurements can be read through the VSHUNT, VBUS, and DIETEMP registers, respectively. The digital output in VSHUNT and VBUS registers is 16-bits. The shunt voltage measurement can be positive or negative due to bidirectional currents in the system; therefore the data value in VSHUNT can be positive or negative. The VBUS data value is always positive. The output data can be directly converted into voltage by multiplying the digital value by its respective resolution size. The digital output in the DIETEMP register is 12-bit and can be directly converted to °C by multiplying by the above resolution size. This output value can also be positive or negative.

Furthermore, the device provides the flexibility to report calculated current in Amperes, power in Watts as described in Section 8.1.2.