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

3.3.2 THD and THD+N Results

Table 3-6 and Table 3-7 show the THD+N measurement results across various amplitudes, tones, and sample rates.

Table 3-6 DAC11001A THD+N Measurement Results
INPUT AMPLITUDE TONE FREQUENCY SAMPLE RATE
48kSPS 96kSPS 192kSPS
0dBFS 1kHz –107dB –107dB –108dB
2kHz –94dB –101dB –106dB
5kHz –56dB –74dB –92dB
10kHz –49dB –45dB –73dB
–60dBFS 1kHz –55dB –51dB –50dB
2kHz –54dB –50dB –49dB
5kHz –56dB –50dB –49dB
10kHz –57dB –50dB –50dB
Table 3-7 DAC11001B THD+N Measurement Results
INPUT AMPLITUDE TONE FREQUENCY SAMPLE RATE
48kSPS 96kSPS 192kSPS
0dBFS 1kHz –111dB –108dB –108dB
2kHz –110dB –108dB –108dB
5kHz –75dB –97dB –106dB
10kHz –47dB –69dB –92dB
–60dBFS 1kHz –55dB –51dB –50dB
2kHz –53dB –50dB –49dB
5kHz –55dB –50dB –40dB
10kHz –57dB –50dB –50dB

Figure 3-7 shows the THD+N improving as the input level magnitude increases. This is because the magnitude of the DAC output is increasing as the noise level stays the same. The linear decline of the THD+N value shows that the THD+N is dominated by noise. The headphone amplitude is around 12dB lower than the line amplitude, which is reflected in the slightly worse THD+N results.

TIDA-060031 Line and Headphone Output THD+N vs Input Level
500Hz sine-wave input, sampling frequency = 192kSPS
Figure 3-7 Line and Headphone Output THD+N vs Input Level

The behavior shown in Figure 3-8 demonstrates the enhanced performance of the DAC11001B track-and-hold design compared to the DAC11001A. The DAC11001B maintains a flatter THD+N profile across higher frequencies.

TIDA-060031 Line Output THD+N vs Frequency and Amplitude TIDA-060031 Line Output THD+N vs Frequency and Amplitude
Sampling frequency = 192kSPS
Figure 3-8 Line Output THD+N vs Frequency and Amplitude

Figure 3-9 shows the noise and harmonic performance of the DAC11001 with a 10k tone.

TIDA-060031 FFT of Audible Range With 10kHz Sine Wave
Sampling frequency = 192kSPS
Figure 3-9 FFT of Audible Range With 10kHz Sine Wave