TIDUEV2 October   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Differences Between Audio DACs and Precision DACs
      2. 2.2.2 Right-Justified I2S to Daisy-Chained SPI Conversion
    3. 2.3 Highlighted Products
      1. 2.3.1 DAC11001
      2. 2.3.2 OPA1656
      3. 2.3.3 OPA1622
      4. 2.3.4 OPA2828
    4. 2.4 System Design Theory
      1. 2.4.1 Output Glitch
      2. 2.4.2 Sample Rate Dependence in Precision DACs
      3. 2.4.3 System Noise
      4. 2.4.4 DAC11001A vs DAC11001B
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 Required External Power Supplies
      2. 3.1.2 Jumper Definitions
      3. 3.1.3 Selecting I2S Source
        1. 3.1.3.1 USB I2S Source
        2. 3.1.3.2 SPDIF I2S Source
        3. 3.1.3.3 External PSIA I2S Source
    2. 3.2 Software Requirements
      1. 3.2.1 Installing the XMOS USB 2.0 Driver
      2. 3.2.2 Setting USB Sample Rate
    3. 3.3 Testing and Results
      1. 3.3.1 Measuring Total Harmonic Distortion and Noise
      2. 3.3.2 THD and THD+N Results
      3. 3.3.3 Measuring Dynamic Range
      4. 3.3.4 Dynamic Range Results
      5. 3.3.5 Measuring Signal-to-Noise Ratio
      6. 3.3.6 SNR Results
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  11. 5Related Documentation
    1. 5.1 Support Resources
    2. 5.2 Trademarks
  12. 6About the Author

2.3.2 OPA1656

The OPA1656 is a Burr-Brown™ operational amplifier (op amp) designed specifically for audio and industrial applications where maintaining signal fidelity is crucial. The FET-input architecture achieves a low 2.9nV/√Hz voltage noise density and 6fA/√Hz current noise density, allowing for very low noise performance in a wide variety of circuits. The high bandwidth and high open-loop-gain design of the OPA1656 delivers a low distortion of 0.000035% (–129dB) at 20kHz and improves audio signal fidelity across the full audio bandwidth. This device also features excellent output current drive capability, offering rail-to-rail output swing to within 250mV of the power supplies with a 2kΩ load, and can deliver 100mA of output current.

The OPA1656 operates over a very wide supply range of ±2.25V to ±18V or 4.5V to 36V on 3.9mA of supply current to accommodate the power supply constraints of many types of audio products. The temperature range is specified from –40°C to +125°C. The device is offered in an 8-pin SOIC package.