SBOS365G may   2006  – may 2023 OPA2365 , OPA365

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information: OPA365
    5. 7.5 Thermal Information: OPA2365
    6. 7.6 Electrical Characteristics
    7. 7.7 Typical Characteristics
  9. 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 Input and ESD Protection
      3. 8.3.3 Capacitive Loads
      4. 8.3.4 Achieving an Output Level of Zero Volts (0 V)
      5. 8.3.5 Active Filtering
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Basic Amplifier Configurations
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
    3. 9.3 System Examples
      1. 9.3.1 Driving an Analog-to-Digital Converter
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 PSpice® for TI
        2. 10.1.1.2 TINA-TI™ Simulation Software (Free Download)
        3. 10.1.1.3 DIP-Adapter-EVM
        4. 10.1.1.4 DIYAMP-EVM
        5. 10.1.1.5 TI Reference Designs
        6. 10.1.1.6 Filter Design Tool
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.4 Achieving an Output Level of Zero Volts (0 V)

Certain single-supply applications require the op amp output to swing from 0 V to a positive full-scale voltage and have high accuracy. An example is an op amp employed to drive a single-supply ADC having an input range from 0 V to 5 V. Rail-to-rail output amplifiers with very light output loading can achieve an output level within millivolts of 0 V (or +VS at the high end), but not 0 V. Furthermore, the deviation from 0 V only becomes greater as the load current required increases. This increased deviation is a result of limitations of the CMOS output stage.

When a pulldown resistor is connected from the amplifier output to a negative voltage source, the OPAx365 can achieve an output level of 0 V, and even a few millivolts below 0 V. Below this limit, nonlinearity and limiting conditions become evident. Figure 8-4 illustrates a circuit using this technique.

A pulldown current of approximately 500 μA is required when the OPAx365 is connected as a unity-gain buffer. A practical termination voltage (VNEG) is −5 V, but other convenient negative voltages also can be used. Pulldown resistor RL is calculated from RL = [(VO − VNEG) / (500 μA)].

Using a minimum output voltage (VO) of 0 V, RL = [0 V − (−5 V)] / (500 μA)] = 10 kΩ. Keep in mind that lower termination voltages result in smaller pulldown resistors that load the output during positive output voltage excursions.

Note:

This technique does not work with all op amps; apply only to op amps such as the OPAx365 that have been specifically designed to operate in this manner. Also, operating the OPAx365 output at 0 V changes the output-stage operating conditions, resulting in somewhat lower open-loop gain and bandwidth.

Keep these precautions in mind when driving a capacitive load because these conditions can affect circuit transient response and stability.

GUID-B966EB6C-967A-4539-9EDD-CC765C3BB0A5-low.gif Figure 8-4 Swing-to-Ground