SBOS512E March   2010  – November 2020 OPA2365-Q1 , OPA365-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Operating Characteristics
      2. 7.3.2 Basic Amplifier Configurations
      3. 7.3.3 Input and ESD Protection
      4. 7.3.4 Rail-to-Rail Input
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Capacitive Loads
      2. 8.1.2 Achieving an Output Level of Zero Volts (0 V)
      3. 8.1.3 Active Filtering
      4. 8.1.4 Driving an ADS7822-Q1 Analog-to-Digital Converter
      5. 8.1.5 Driving ADS1115-Q1 Analog-to-Digital Converter
    2. 8.2 Typical Application
      1. 8.2.1 Fast Settling Peak Detector
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Bandpass Filter 1.5 kHz to 160 kHz and 40-db Flat Gain
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  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 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.1.3 Active Filtering

The OPA365-Q1 device is well-suited for active filter applications requiring a wide bandwidth, fast slew rate, low-noise, and single-supply operational amplifier. Figure 8-3 shows a 500 kHz, 2nd-order, low-pass filter utilizing 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 ideal for applications requiring predictable gain characteristics such as the anti-aliasing filter used ahead of an ADC.

GUID-5E08A393-C893-4A27-B4DF-1B9BECF83C24-low.gifFigure 8-3 Second-Order Butterworth 500-kHz Low-Pass Filter

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 these options:

  1. adding an inverting amplifier;
  2. adding an additional 2nd-order MFB stage;
  3. using a noninverting filter topology such as the Sallen-Key (shown in Figure 8-4).
MFB and Sallen-Key, low-pass and high-pass filter synthesis is quickly accomplished using TI's FilterPro program. This software is available as a free download at www.ti.com.

GUID-8F0C403F-93DB-408E-B49B-476F141AC7F3-low.gifFigure 8-4 Configured as a 3-Pole, 20 kHz, Sallen-Key Filter