SLOS884B September   2014  – December 2018 OPA2320-Q1 , OPA320-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Zero Crossover Distortion: Low Offset Voltage
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics:
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input and ESD Protection
      2. 7.3.2 Feedback Capacitor Improves Response
      3. 7.3.3 EMI Susceptibility And Input Filtering
      4. 7.3.4 Output Impedance
      5. 7.3.5 Capacitive Load and Stability
      6. 7.3.6 Overload Recovery Time
    4. 7.4 Device Functional Modes
      1. 7.4.1 Rail-to-Rail Input
      2. 7.4.2 Phase Reversal
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Transimpedance Amplifier
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Optimizing The Transimpedance Circuit
        3. 8.2.1.3 Application Curves
      2. 8.2.2 High-Impedance Sensor Interface
      3. 8.2.3 Driving ADCs
      4. 8.2.4 Active Filter
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.4 Active Filter

The OPAx320-Q1 is an excellent choice for active filter applications that require a wide bandwidth, fast slew rate, low-noise, single-supply operational amplifier. Figure 43 shows a 500 kHz, second-order, low-pass filter using the multiple-feedback (MFB) topology. The components have been selected to provide a maximally-flat Butterworth response. Beyond the cutoff frequency, roll-off is –40 dB/dec. The Butterworth response is excellent for applications requiring predictable gain characteristics, such as the antialiasing filter used in front of an ADC.

One point to observe when considering the MFB filter is that the output is inverted, relative to the input. If this inversion is not required, or not desired, a noninverting output can be achieved through one of the following options:

  1. adding an inverting amplifier
  2. adding an additional second-order MFB stage
  3. using a noninverting filter topology, such as the Sallen-Key
OPA320-Q1 OPA2320-Q1 ai_2order_lopass_filt_slos884.gifFigure 43. Second-Order Butterworth 500-kHz Low-Pass Filter
OPA320-Q1 OPA2320-Q1 ai_sallen_key_slos884.gifFigure 44. OPAx320-Q1 Configured as a Three-Pole, 20-kHz, Sallen-Key Filter