SBOSAI7B November   2023  – July 2024 OPA2891 , OPA891

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 - OPA891
    5. 5.5 Thermal Information - OPA2891
    6. 5.6 Electrical Characteristics - RL = 150Ω
    7. 5.7 Electrical Characteristics - RL = 1kΩ
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagrams
    3. 6.3 Feature Description
      1. 6.3.1 Offset Nulling
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Driving a Capacitive Load
      2. 7.1.2 Low-Pass Filter Configurations
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Selection of Multiplexer
        2. 7.2.2.2 Signal Source
        3. 7.2.2.3 Driving Amplifier
        4. 7.2.2.4 Driving Amplifier Bandwidth Restriction
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 General PowerPAD™ Integrated Circuit Package Design Considerations
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.1 Driving a Capacitive Load

The OPAx891 are internally compensated to maximize bandwidth and slew-rate performance. To maintain stability, take additional precautions when driving capacitive loads with a high-performance amplifier. As a result of the internal compensation, significant capacitive loading directly on the output node decreases the device phase margin, and potentially lead to high-frequency ringing or oscillations. Therefore, for capacitive loads greater than 10pF, place an isolation resistor in series with the output of the amplifier. Figure 7-1 shows this configuration. For most applications, a minimum resistance of 20Ω is recommended. In 75Ω transmission systems, setting the series resistor value to 75Ω is a beneficial choice because this value isolates any capacitance loading and provides source impedance matching.

OPA891 OPA2891 Driving a Capacitive Load Figure 7-1 Driving a Capacitive Load