SLAAEO8 October   2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1 , MSPM0G1105 , MSPM0G1106 , MSPM0G1107 , MSPM0G1505 , MSPM0G1506 , MSPM0G1507 , MSPM0G1519 , MSPM0G3105 , MSPM0G3105-Q1 , MSPM0G3106 , MSPM0G3106-Q1 , MSPM0G3107 , MSPM0G3107-Q1 , MSPM0G3505 , MSPM0G3505-Q1 , MSPM0G3506 , MSPM0G3506-Q1 , MSPM0G3507 , MSPM0G3507-Q1 , MSPM0G3519 , MSPM0L1105

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1ADC Introduction
    1. 1.1 SAR ADC Principle
    2. 1.2 ADC Parameters
      1. 1.2.1 Static Parameters
      2. 1.2.2 Dynamic Parameters
        1. 1.2.2.1 AC Parameters
        2. 1.2.2.2 DC Parameters
  5. 2ADC Noise Analysis
    1. 2.1 ADC Noise Classification
      1. 2.1.1 ADC Noise
      2. 2.1.2 Reference Noise
      3. 2.1.3 Power Supply Noise
      4. 2.1.4 ADC Input Noise
      5. 2.1.5 Clock Jitter
    2. 2.2 How to Reduce Noise
      1. 2.2.1 Reducing Input Noise Through RC Filtering
      2. 2.2.2 Layout Suggestions
      3. 2.2.3 Improving Signal-to-Noise Ratio
      4. 2.2.4 Choose a Suitable Reference Voltage Source
      5. 2.2.5 Software Methods for Reducing Noise
  6. 3ADC Oversampling
    1. 3.1 Sampling Rate
    2. 3.2 Extraction
    3. 3.3 Application Conditions
  7. 4ADC Application Based on MSPM0
    1. 4.1 ADC Configuration of MSPM0
    2. 4.2 ADC DC Test Based on MSPM0G3507 ADC EVM Board
      1. 4.2.1 Software/Hardware Configuration
        1. 4.2.1.1 Hardware
        2. 4.2.1.2 Software
      2. 4.2.2 Test Result
      3. 4.2.3 Result Analysis and Conclusion

1.2.1 Static Parameters

  • Differential Nonlinearity Error (DNL)

    Differential nonlinearity error is the maximum deviation between the actual step and the ideal step during the ADC analog-to-digital conversion process, where the ideal step refers to 1LSB. DNL exceeding 1LSB results in missing codes in the ADC digital result, meaning that a certain digital code will disappear in the output result.

    Equation 1.                                         DNL = Actual   Step - 1 LSB
  • Integral Nonlinearity Error (INL)

    Integral nonlinear error is the deviation between a certain conversion voltage and the ideal conversion voltage during the ADC conversion process, which reflects the integration of DNL. The measurement of this value was carried out after compensating for offset error and gain error. By measuring the conversion voltage of each digital code, the INL of each code point can be obtained. Only the maximum INL value is provided in the ADC data manual.

    Equation 2.                               INL = the   kth   actual   conversion   voltage - ( k - 0 . 5 ) LSB
  • Offset Error (EO)

    Offset error is the deviation between the voltage at the first actual conversion and the first ideal conversion when the ADC increases from a low voltage. The first conversion occurs when the digital ADC output changes from 0 to 1. For an ideal ADC, when the analog input is between 0.5 LSB and 1.5 LSB, the digital output should be 1, thus the first ideal conversion occurs at 0.5 LSB. So offset error calculation formula is:

    Equation 3.                               EO = the   first   actual   conversion   voltage - 0 . 5 LSB
  • Gain Error (EG)

    Gain error is the voltage deviation between the last actual conversion voltage and the last ideal conversion voltage, and this value is measured after correcting the offset error. Taking a 12-bit ADC as an example, the last actual conversion occurs when output digital result changes from 0xFFE to 0xFFF, which corresponding to a voltage of VREF+ - 0.5 LSB. Therefore, the calculation formula is:

    Equation 4.                           EG = the   last   actual   conversion   voltage -   ( VREF + - 0 . 5 LSB )