SBOSA77A March   2023  – April 2024 OPA928

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics: 4.5V ≤ VS < 8V
    6. 5.6 Electrical Characteristics: 8V ≤ VS ≤ 16V
    7. 5.7 Electrical Characteristics: 16V < VS ≤ 36V
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Guard Buffer
      2. 6.3.2 Input Protection
      3. 6.3.3 Thermal Protection
      4. 6.3.4 Capacitive Load and Stability
      5. 6.3.5 EMI Rejection
      6. 6.3.6 Common-Mode Voltage Range
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Contamination Considerations
      2. 7.1.2 Guarding Considerations
      3. 7.1.3 Single-Supply Considerations
      4. 7.1.4 Humidity Considerations
      5. 7.1.5 Dielectric Relaxation
      6. 7.1.6 Shielding
    2. 7.2 Typical Applications
      1. 7.2.1 High-Impedance Amplifier
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Transimpedance Amplifier
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
          1. 7.2.2.2.1 Input Bias
          2. 7.2.2.2.2 Offset Voltage
          3. 7.2.2.2.3 Stability
          4. 7.2.2.2.4 Noise
      3. 7.2.3 Improved Diode Limiter
      4. 7.2.4 Instrumentation Amplifier
    3. 7.3 Power-Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Examples
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 PSpice® for TI
        2. 8.1.1.2 TINA-TI™ Simulation Software (Free Download)
        3. 8.1.1.3 TI Reference Designs
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.4 Capacitive Load and Stability

The OPA928 features a patented output stage capable of driving large capacitive loads. Increasing the gain enhances the ability of the amplifier to drive greater capacitive loads. The particular op-amp circuit configuration, layout, gain, and output loading are some of the factors to consider when establishing whether an amplifier can be stable in operation.

For additional drive capability, insert a small isolation resistor (RISO) in series with the output; Figure 6-1 shows this resistor. This resistor significantly reduces ringing while maintaining dc performance for purely capacitive loads. However, if there is a resistive load in parallel with the capacitive load, a voltage divider is created, introducing a gain error at the output and slightly reducing the output swing. The error introduced is proportional to the ratio RISO / RL, and is generally negligible at low output levels. RISO modifies the open-loop gain of the system for increased phase margin.

GUID-20240403-SS0I-VSMM-ZXB2-VGGMP5VS94XV-low.svg Figure 6-1 Extending Capacitive Load Drive With the OPA928