SBOS259F September   2002  – June 2018 OPA2363 , OPA2364 , OPA363 , OPA364 , OPA4364

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Single-Supply Microphone Preamplifier
  4. 4 Revision History
  5. 5 Device Comparison Table
    1. 5.1 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions: OPA363
    2.     Pin Functions: OPA2363
    3.     Pin Functions: OPA364
    4.     Pin Functions: OPA2364
    5.     Pin Functions: OPA4364
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information: OPA363
    5. 7.5  Thermal Information: OPA364
    6. 7.6  Thermal Information: OPA2363
    7. 7.7  Thermal Information: OPA2364
    8. 7.8  Thermal Information: OPA4364
    9. 7.9  Electrical Characteristics
    10. 7.10 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Rail-to-Rail Input
      2. 8.3.2 Operating Voltage
      3. 8.3.3 Capacitive Load
      4. 8.3.4 Input and ESD Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Enable Function
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Achieving Output Swing to the Op Amp Negative Rail
      2. 9.1.2 Directly Driving the ADS8324 and the MSP430
      3. 9.1.3 Audio Applications
      4. 9.1.4 Active Filtering
    2. 9.2 Typical Application
      1. 9.2.1 Single-Supply Electret Microphone Preamplifier
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 TINA-TI™ (Free Software Download)
        2. 12.1.1.2 DIP Adapter EVM
        3. 12.1.1.3 Universal Op Amp EVM
        4. 12.1.1.4 TI Precision Designs
        5. 12.1.1.5 WEBENCH Filter Designer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resource
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 Capacitive Load

The OPAx363 and OPAx364 series op amps can drive a wide range of capacitive loads. However, all op amps under certain conditions may become unstable. Op amp configuration, gain, and load value are a few of the factors to consider when determining stability. An op amp in unity-gain configuration is the most susceptible to the effects of capacitive load. The capacitive load reacts with the output resistance of the op amp to create a pole in the small-signal response, which degrades the phase margin.

In unity gain, the OPAx363 and OPAx364 series op amps perform well with a pure capacitive load up to approximately 1000 pF. The equivalent series resistance (ESR) of the loading capacitor may be sufficient to allow the OPA363 and OPA364 to directly drive very large capacitive loads ( greater than 1 µF). Increasing gain enhances the ability of the amplifier to drive more capacitance; see Figure 13.

One method of improving capacitive load drive in the unity-gain configuration is to insert a 10-Ω to 20-Ω resistor in series with the output, as shown in Figure 22. This resistor significantly reduces ringing with large capacitive loads. However, if there is a resistive load in parallel with the capacitive load, the load creates a voltage divider, introduces a DC error at the output, and slightly reduces output swing. This error may be insignificant. For example, with RL = 10 kΩ and RS = 20 Ω, there is an approximate 0.2% error at the output.

OPA363 OPA2363 OPA364 OPA2364 OPA4364 ai_improving_cload_drive_bos259.gifFigure 22. Improving Capacitive Load Drive