What are the ADC specifications?
The ADC specifications that describe this type of accuracy are offset error, full-scale error, differential nonlinearity (DNL) , and integral nonlinearity (INL) . DC accuracy, and resulting absolute error are determined by four specs—offset, full-scale/gain error, INL, and DNL.
What is DNL DAC?
Differential nonlinearity (acronym DNL) is a commonly used measure of performance in digital-to-analog (DAC) and analog-to-digital (ADC) converters. It is a term describing the deviation between two analog values corresponding to adjacent input digital values.
Why linearity error occurs in DAC?
However, due to technological limitations, ADCs and even DACs are not ideal. When that happens, the ADC’s linearity is severely impacted. Therefore, DNL is defined as the maximum deviation from one LSB between two consecutive levels, over the entire transfer function. In an electronic system, linearity is important.
How is ADC INL measured?
INL can be defined as the deviation in LSB of the actual transfer function of the ADC from the ideal transfer curve. INL can be estimated using DNL at each step by calculating the cumulative sum of DNL errors up to that point. In reality, INL is measured by plotting the ADC transfer characteristics as explained below.
When does an ADC have DNL error ≥ 1 LSB?
If an ADC has DNL error ≥ -1 LSB and ≤ 1 LSB, it will be monotonic. Integral non-linearity (INL): INL is a measure of how closely the ADC output matches its ideal response. INL can be defined as the deviation in LSB of the actual transfer function of the ADC from the ideal transfer curve.
How is the INL of an ADC calculated?
INL can be defined as the deviation in LSB of the actual transfer function of the ADC from the ideal transfer curve. INL can be estimated using DNL at each step by calculating the cumulative sum of DNL errors up to that point. In reality, INL is measured by plotting the ADC transfer characteristics as explained below.
How is the code width of an ADC measured?
The code width (or LSB) of an ADC is shown in Equation 1. The voltage difference between each code transition should be equal to one LSB, as defined in Equation 1. Deviation of each code from an LSB is measured as DNL.
How to calculate integral non-linearity of ADC?
Integral non-linearity (INL): INL is a measure of how closely the ADC output matches its ideal response. INL can be defined as the deviation in LSB of the actual transfer function of the ADC from the ideal transfer curve. INL can be estimated using DNL at each step by calculating the cumulative sum of DNL errors up to that point.