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

7.3.6 Capacitive Load and Stability

The dynamic characteristics of the OPAx187 are optimized for a range of common operating conditions. The combination of low closed-loop gain and high capacitive loads decreases the amplifier phase margin and can lead to gain peaking or oscillations. As a result, larger capacitive loads must be isolated from the output. The simplest way to achieve this isolation is to add a small resistor (for example, ROUT equal to 50 Ω) in series with the output. Figure 38 illustrates small-signal overshoot versus capacitive load for several values of ROUT. Also, for details of analysis techniques and application circuits, refer to the Feedback Plots Define Op Amp AC Performance application report, available for download from www.ti.com.

OPA187 OPA2187 OPA4187 C207_SBOS701.png
G = 1, RL = 10 kΩ, 10-mV Output Step
Figure 38. Small-Signal Overshoot vs Capacitive Load