SBOS937D October   2020  – December 2023 OPA3S328

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
    6. 5.6 Timing Diagram
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Switch Characterization Configurations
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Low Operating Voltage
      2. 7.3.2 Input and ESD Protection
      3. 7.3.3 Programmable Switches
      4. 7.3.4 Rail-to-Rail Input
      5. 7.3.5 Phase Reversal
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-Down Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Capacitive Load and Stability
      2. 8.1.2 EMI Susceptibility and Input Filtering
      3. 8.1.3 Transimpedance Amplifier
        1. 8.1.3.1 Optimizing the Transimpedance Circuit
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 PSpice® for TI
        2. 9.1.1.2 TINA-TI™ Simulation Software (Free Download)
        3. 9.1.1.3 TI Reference Designs
        4. 9.1.1.4 Filter Design Tool
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.1.1 Capacitive Load and Stability

The OPA3S328 is designed to be used in high-speed applications for TIA and ADC input-driving amplifiers. As with all op amps, there can be specific instances where the OPA3S328 becomes unstable. The particular op-amp circuit configuration, layout, gain, and output loading are some of the factors to consider when establishing whether an amplifier is stable in operation. An op amp in the unity-gain (1‑V/V) buffer configuration and driving a capacitive load exhibits a greater tendency to become unstable than an amplifier operated at a higher noise gain, as seen in Figure 5-29. The capacitive load, in conjunction with the op amp output resistance, creates a pole within the feedback loop that degrades the phase margin. The degradation of the phase margin increases as the capacitive loading increases. When operating in the unity-gain configuration, the OPA3S328 remains stable with a pure capacitive load up to 100 pF.

One technique to increase the capacitive load drive capability of an amplifier operating in a unity-gain configuration is to insert a small resistor (RS), typically 10 Ω to 50 Ω, in series with the output. Figure 8-2 shows this technique. This resistor significantly reduces the overshoot and ringing associated with large capacitive loads.

GUID-20210912-SS0I-RT9J-BNCV-VRSGR8NWFBD4-low.svg Figure 8-1 Improving Capacitive Load Drive