SLYS025A January   2021  – May 2022 INA238

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 INA238 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

8.1.3 ADC Output Data Rate and Noise Performance

The INA238 noise performance and effective resolution depend on the ADC conversion time. The device also supports digital averaging which can further help decrease digital noise. The flexibility of the device to select ADC conversion time and data averaging offers increased signal-to-noise ratio and achieves the highest dynamic range with lowest offset. The profile of the noise at lower signals levels is dominated by the system noise that is comprised mainly of 1/f noise or white noise. The INA238 effective resolution of the ADC can be increased by increasing the conversion time and increasing the number of averages.

Table 8-2 summarizes the output data rate conversion settings supported by the device. The fastest conversion setting is 50 µs. Typical noise-free resolution is represented as Effective Number of Bits (ENOB) based on device measured data. The ENOB is calculated based on noise peak-to-peak values, which assures that full noise distribution is taken into consideration.

Table 8-2 INA238 Noise Performance
ADC CONVERSION TIME PERIOD [µs]OUTPUT SAMPLE AVERAGING [SAMPLES]OUTPUT SAMPLE PERIOD [ms]NOISE-FREE ENOB
(±163.84-mV)
(ADCRANGE = 0)		NOISE-FREE ENOB
(±40.96-mV)
(ADCRANGE = 1)
5010.0512.59.9
840.08412.710.5
1500.1513.411.4
2800.2813.712.2
5400.5414.112.4
10521.05214.112.7
20742.07415.713.1
41204.1215.713.4
5040.212.710.6
840.33613.711.4
1500.614.112.2
2801.1214.712.7
5402.1615.713.4
10524.20815.714.1
20748.29615.714.7
412016.4815.714.7
50160.813.711.5
841.34415.712.7
1502.415.713.4
2804.4815.713.7
5408.6415.714.1
105216.83215.714.7
207433.18415.715.7
412065.9216.015.7
50643.215.712.5
845.37615.713.7
1509.615.714.7
28017.9215.714.7
54034.5616.014.7
105267.32816.015.7
2074132.73616.015.7
4120263.6816.015.7
501286.415.713.1
8410.75215.714.1
15019.215.714.7
28035.8416.015.7
54069.1216.015.7
1052134.65616.015.7
2074265.47216.015.7
4120527.3616.016.0
5025612.815.713.7
8421.50415.714.7
15038.415.715.7
28071.6816.015.7
540138.2416.015.7
1052269.31216.016.0
2074530.94416.016.0
41201054.7216.016.0
5051225.615.714.1
844316.015.7
15076.816.015.7
280143.3616.015.7
540276.4816.015.7
1052538.62416.016.0
20741061.88816.016.0
41202109.4416.016.0
50102451.215.714.7
8486.01615.715.7
150153.616.016.0
280286.7216.016.0
540552.9616.016.0
10521077.24816.016.0
20742123.77616.016.0
41204218.8816.016.0