SBOSA00B December   2019  – August 2020 OPA1637

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 Parameter Measurement Information
    1. 7.1 Characterization Configuration
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Super-Beta Input Bipolar Transistors
      2. 8.3.2 Power Down
      3. 8.3.3 Flexible Gain Setting
      4. 8.3.4 Amplifier Overload Power Limit
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Driving Capacitive Loads
      2. 9.1.2 Operating the Power-Down Feature
      3. 9.1.3 I/O Headroom Considerations
      4. 9.1.4 Noise Performance
    2. 9.2 Typical Applications
      1. 9.2.1 Current-Output Audio DAC Buffer to Class-D Amplifier
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 An MFB Filter Driving an ADC Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Differential Microphone Input to Line Level
        1. 9.2.3.1 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Board Layout Recommendations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2 An MFB Filter Driving an ADC Application

A common application use case for fully-differential amplifiers is to easily convert a single-ended signal into a differential signal to drive a differential input source, such as an ADC or class-D amplifier. Figure 9-8 shows an example of the OPA1637 used to convert a single-ended, low-voltage signal audio source, such as a small electret microphone, and deliver a low-noise differential signal that is common-mode shifted to the center of the ADC input range. A multiple-feedback (MFB) configuration is used to provide a Butterworth filter response, giving a 40-dB/decade rolloff with a –3-dB frequency of 30 kHz.

GUID-20200813-CA0I-JQ2S-78CM-ZZRDFCBQBPKS-low.gifFigure 9-8 Example 30-kHz Butterworth Filter