SBOSA20A February   2021  – May 2022 INA237

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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. 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. 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. 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

Application Curves

Figure 8-3 and Figure 8-4 show the ALERT pin response to a bus overvoltage fault with a conversion time of 50 μs, averaging set to 1, and the SLOWALERT bit set to 0 for bus only conversions. For these scope shots, persistence was enabled on the ALERT channel to show the variation in the alert response for many sequential fault events. If the magnitude of the fault is sufficient the ALERT response can be as fast as one quarter of the ADC conversion time as shown in Figure 8-3. For fault conditions that are just exceeding the limit threshold, the response time for the ALERT pin can vary from approximately 0.5 to 1.5 conversion cycles as shown in Figure 8-4. Variation in the alert response exists because the external fault event is not synchronized to the internal ADC conversion start. Also the ADC is constantly sampling to get a result, so the response time for fault events starting from zero will slower than fault events starting from values near the set fault threshold. Since the timing of the alert can be difficult to predict, applications where the alert timing is critical should assume a alert response equal to 1.5 times the ADC conversion time for bus voltage or shunt voltage only conversions.

GUID-20201207-CA0I-7VRD-S9JB-HRC3MGZKFJLJ-low.gifFigure 8-3 Alert Response Time (Sampled Values Significantly Above Threshold)
GUID-20201207-CA0I-FDNZ-7HCJ-7KZDJ2NWLGMX-low.gifFigure 8-4 Alert Response Time (Sampled Values Slightly Above Threshold)