SBOS547A June   2011  – August 2015 INA226

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 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 Basic ADC Functions
        1. 7.3.1.1 Power Calculation
        2. 7.3.1.2 Alert Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 Averaging and Conversion Time Considerations
      2. 7.4.2 Filtering and Input Considerations
    5. 7.5 Programming
      1. 7.5.1 Programming the Calibration Register
      2. 7.5.2 Programming the Power Measurement Engine
        1. 7.5.2.1 Calibration Register and Scaling
      3. 7.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
      4. 7.5.4 Default Settings
      5. 7.5.5 Bus Overview
        1. 7.5.5.1 Serial Bus Address
        2. 7.5.5.2 Serial Interface
        3. 7.5.5.3 Writing to and Reading from the INA226
          1. 7.5.5.3.1 High-Speed I2C Mode
        4. 7.5.5.4 SMBus Alert Response
    6. 7.6 Register Maps
      1. 7.6.1  Configuration Register (00h) (Read/Write)
      2. 7.6.2  Shunt Voltage Register (01h) (Read-Only)
      3. 7.6.3  Bus Voltage Register (02h) (Read-Only)
      4. 7.6.4  Power Register (03h) (Read-Only)
      5. 7.6.5  Current Register (04h) (Read-Only)
      6. 7.6.6  Calibration Register (05h) (Read/Write)
      7. 7.6.7  Mask/Enable Register (06h) (Read/Write)
      8. 7.6.8  Alert Limit Register (07h) (Read/Write)
      9. 7.6.9  Manufacturer ID Register (FEh) (Read-Only)
      10. 7.6.10 Die ID Register (FFh) (Read-Only)
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 High-Side Sensing Circuit Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 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 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Community 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 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Validate and test the design implementation to confirm system functionality.

8.1 Application Information

The INA226 is a current shunt and power monitor with an I2C™ compatible interface. The device monitors both a shunt voltage drop and bus supply voltage. Programmable calibration value, conversion times, and averaging, combined with an internal multiplier, enable direct readouts of current in amperes and power in watts.

8.2 Typical Applications

8.2.1 High-Side Sensing Circuit Application

INA226 ai_example_sbos743.gifFigure 27. Typical Circuit Configuration, INA226

8.2.1.1 Design Requirements

INA226 measures the voltage developed across a current-sensing resistor (RSHUNT) when current passes through it. The device also measures the bus supply voltage and can calculate power when calibrated. It comes with alert capability where the alert pin can be programmed to respond to a user-defined event or to a conversion ready notification. This design illustrates the ability of the alert pin to respond to a set threshold.

8.2.1.2 Detailed Design Procedure

The Alert pin can be configured to respond to one of the five alert functions described in the Alert Pin section. The alert pin must to be pulled up to the VVS pin voltage via the pull-up resistors. The configuration register is set based on the required conversion time and averaging. The Mask/Enable Register is set to identify the required alert function and the Alert Limit Register is set to the limit value used for comparison.

8.2.1.3 Application Curves

Figure 28 shows the Alert pin response to a shunt voltage over-limit of 80 mV for a conversion time (tCT) of 1.1 ms and averaging set to 1. Figure 29 shows the response for the same limit but with the conversion time reduced to 140 µs.

INA226 D002_SBOS743.gif
See Table 19 tCT = 1.1 ms
See Table 21 See Table 22
Figure 28. Alert Response
INA226 D001_SBOS743.gif
See Table 20 tCT = 140 µs
See Table 21 See Table 22
Figure 29. Alert Response

Table 19. Configuration Register (00h) Settings for Figure 28 (Value = 4025h)

BIT # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
BIT
NAME		 RST — — — AVG2 AVG1 AVG0 VBUSCT2 VBUSCT1 VBUSCT0 VSHCT2 VSHCT1 VSHCT0 MODE3 MODE2 MODE1
POR VALUE 0 1 0 0 0 0 0 0 0 0 1 0 0 1 0 1

Table 20. Configuration Register (00h) Settings for Figure 29 (Value = 4005h)

BIT # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
BIT
NAME		 RST — — — AVG2 AVG1 AVG0 VBUSCT2 VBUSCT1 VBUSCT0 VSHCT2 VSHCT1 VSHCT0 MODE3 MODE2 MODE1
POR VALUE 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1

Table 21. Mask/Enable Register (06h) Settings for Figure 28 and Figure 29 (Value = 8000h)

BIT # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
BIT
NAME		 SOL SUL BOL BUL POL CNVR — — — — — AFF CVRF OVF APOL LEN
POR VALUE 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 22. Alert Limit Register (07h) Settings for Figure 28 and Figure 29 (Value = 7D00)

BIT # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
BIT
NAME		 AUL15 AUL14 AUL13 AUL12 AUL11 AUL10 AUL9 AUL8 AUL7 AUL6 AUL5 AUL4 AUL3 AUL2 AUL1 AUL0
POR VALUE 0 1 1 1 1 1 0 1 0 0 0 0 0 0 0 0