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

3.3.6 SNR Results

Table 3-11 and Table 3-12 show the SNR results of the DAC11001A and DAC11001B. Some noise is generated from the digital transmitter, resulting in a slightly worse SNR. The SNR with the digital transmitter turned off is shown in Table 3-13.

Table 3-11 DAC11001A Signal-to-Noise Ratio Measurements
INPUT AMPLITUDETONE FREQUENCYSAMPLE RATE
48kSPS96kSPS192kSPS
100% Full-scale1kHz2.115VRMS2.112VRMS2.112VRMS
0% Full-scale, no ditherN/A1.893µVRMS2.038µVRMS2.29µVRMS
Calculated SNR120.9dB120.3dB119.3dB
Table 3-12 DAC11001B Signal-to-Noise Ratio Measurements
INPUT AMPLITUDE TONE FREQUENCY SAMPLE RATE
48kSPS 96kSPS 192kSPS
100% Full-scale 1kHz 2.115VRMS 2.112VRMS 2.112VRMS
0% Full-scale, no dither N/A 1.858µVRMS 2.039µVRMS 2.325µVRMS
Calculated SNR 121.1dB 120.3dB 119.2dB
Table 3-13 DAC11001 Signal-to-Noise Ratio with no Digital
INPUT AMPLITUDE TONE FREQUENCY RESULT
100% Full-scale 1kHz 2.115VRMS
0% Full-scale, no TX N/A 1.732µVRMS
Calculated SNR 121.7dB