SBOS469H April   2009  – October 2023 INA199

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Basic Connections
      2. 7.3.2 Selecting RS
    4. 7.4 Device Functional Modes
      1. 7.4.1 Input Filtering
      2. 7.4.2 Shutting Down the INA199 Series
      3. 7.4.3 REF Input Impedance Effects
      4. 7.4.4 Using the INA199 With Common-Mode Transients Above 26 V
      5. 7.4.5 Improving Transient Robustness
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Unidirectional Operation
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Bidirectional Operation
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.4.2 Shutting Down the INA199 Series

Although the INA199 series does not have a shutdown pin, the low power consumption of the device allows the output of a logic gate or transistor switch to power the INA199. This gate or switch turns on and turns off the INA199 power-supply quiescent current.

However, in current shunt monitoring applications, there is also a concern for how much current is drained from the shunt circuit in shutdown conditions. Evaluating this current drain involves considering the simplified schematic of the INA199 in shutdown mode shown in Figure 7-3.

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1-MΩ paths from shunt inputs to reference and the INA199 outputs.
Figure 7-3 Basic Circuit for Shutting Down the INA199 With a Grounded Reference

There is typically slightly more than 1-MΩ impedance (from the combination of 1-MΩ feedback and 5-kΩ input resistors) from each input of the INA199 to the OUT pin and to the REF pin. The amount of current flowing through these pins depends on the respective ultimate connection. For example, if the REF pin is grounded, the calculation of the effect of the 1-MΩ impedance from the shunt to ground is straightforward. However, if the reference or operational amplifier is powered when the INA199 is shut down, the calculation is direct; instead of assuming 1-MΩ to ground, however, assume 1-MΩ to the reference voltage. If the reference or operational amplifier is also shut down, some knowledge of the reference or operational amplifier output impedance under shutdown conditions is required. For instance, if the reference source functions as an open circuit when not powered, little or no current flows through the 1-MΩ path.

Regarding the 1-MΩ path to the output pin, the output stage of a disabled INA199 does constitute a good path to ground. Consequently, this current is directly proportional to a shunt common-mode voltage impressed across a 1-MΩ resistor.

Note:

When the device is powered up, there is an additional, nearly constant, and well-matched 25 μA that flows in each of the inputs as long as the shunt common-mode voltage is 3 V or higher. Below 2-V common-mode, the only current effects are the result of the 1-MΩ resistors.