SBOS807E December   2016  – May 2020 OPA187 , OPA2187 , OPA4187

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      OPAx187 Offers Precision Low-Side Current Measurement Capability
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: OPA187
    2.     Pin Functions: OPA2187
    3.     Pin Functions: OPA4187
  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: OPA187
    5. 6.5 Thermal Information: OPA2187
    6. 6.6 Thermal Information: OPA4187
    7. 6.7 Electrical Characteristics: High-Voltage Operation
    8. 6.8 Electrical Characteristics: Low-Voltage Operation
    9. 6.9 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 Operating Characteristics
      2. 7.3.2 Phase-Reversal Protection
      3. 7.3.3 Input Bias Current Clock Feedthrough
      4. 7.3.4 Internal Offset Correction
      5. 7.3.5 EMI Rejection
      6. 7.3.6 Capacitive Load and Stability
      7. 7.3.7 Electrical Overstress
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 High-Side Voltage-to-Current (V-I) Converter
        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 Discrete INA + Attenuation for ADC With 3.3-V Supply
      3. 8.2.3 Bridge Amplifier
      4. 8.2.4 Low-Side Current Monitor
      5. 8.2.5 Programmable Power Supply
      6. 8.2.6 RTD Amplifier With Linearization
  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
        1. 11.1.1.1 TINA-TI™ (Free Software Download)
        2. 11.1.1.2 TI Precision Designs
        3. 11.1.1.3 WEBENCH® Filter Designer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Support Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3 Feature Description

The OPAx187 are unity-gain stable and free from unexpected output phase reversal. These devices use a proprietary, periodic autocalibration technique to provide ultra-low input offset voltage and near zero input offset voltage drift over temp and temperature. For lowest offset voltage and precision performance, optimize circuit layout and mechanical conditions. Avoid temperature gradients that create thermoelectric (Seebeck) effects in the thermocouple junctions formed from connecting dissimilar conductors. Cancel these thermally-generated potentials by making sure they are equal on both input pins. Other layout and design considerations include:

Use low thermoelectric-coefficient conditions (avoid dissimilar metals).

Thermally isolate components from power supplies or other heat sources.

Shield operational amplifier and input circuitry from air currents, such as cooling fans.

Follow these guidelines to reduce the likelihood of junctions being at different temperatures, which may cause thermoelectric voltages of 0.1 µV/°C or higher, depending on the materials used.