ZHCSDO5C April   2015  – September 2023

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 说明
  5. Revision History
  6. Pin Configuration and Functions
  7. 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. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Integrated Shunt Resistor
      2. 7.3.2 Short-Circuit Duration
      3. 7.3.3 Temperature Stability
    4. 7.4 Device Functional Modes
      1. 7.4.1 Amplifier Operation
      2. 7.4.2 Input Filtering
        1. 7.4.2.1 Calculating Gain Error Resulting from External Filter Resistance
      3. 7.4.3 Shutting Down the Device
      4. 7.4.4 Using the Device with Common-Mode Transients Above 36 V
  9. Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Current Summing
        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 Parallel Multiple INA250 Devices for Higher Current
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
      3. 8.2.3 Current Differencing
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 接收文档更新通知
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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Amplifier Operation

The INA250 current-sense amplifier can be configured to measure both unidirectional and bidirectional currents through the reference voltage level applied to the reference pin, REF. The reference voltage connected to REF sets the output level that corresponds with a zero input current condition.  For unidirectional operation, tie the REF pin to ground so that when the current increases, the output signal also increases upwards from this reference voltage (or ground in this case).  For bidirectional currents, an external voltage source can be used as the reference voltage connected to the REF pin to bias up the output.  Set the reference voltage to enable sufficient range above and below this level based on the expected current range to be measured. Positive currents result in an output signal that increases from the zero-current output level set by the reference voltage whereas negative currents result in an output signal that decreases.

For both unidirectional and bidirectional applications, the amplifier transfer function is shown in Equation 1:

Equation 1. VOUT = (ILOAD × GAIN) + VREF

where:

  • ILOAD is the current being measured passing through the internal shunt resistor,
  • GAIN is the corresponding gain (mA/V) of the selected device, and
  • VREF is the voltage applied to the REF pin

As with any difference amplifier, the INA250 common-mode rejection ratio is affected by any impedance present at the REF input. This concern is not a problem when the REF pin is connected directly to a reference or power supply. When using resistive dividers from a power supply or a reference voltage, buffer the REF pin with an op amp.