Contents
What is INL and DNL of ADC?
INL – Integral Non-Linearity: DNL errors accumulate to produce a total Integral Non-Linearity (INL). It is defined as the maximum deviation from the ideal slope of the ADC and is measured from the center of the step. It is expressed as counts. INL is a function of each ADC’s particular architecture.
Which of the following are the specification of ADC?
DC accuracy The ADC specifications that describe this type of accuracy are offset error, full-scale error, differential nonlinearity (DNL) , and integral nonlinearity (INL) . These four specifications build a complete description of an ADC’s absolute accuracy.
What is linearity error?
The linearity error of a system is the maximum deviation of the actual transfer characteristic from a prescribed straight line. Manufacturers specify linearity in various ways, for instance as the deviation in input or output units: Δxmax or Δymax, or as a fraction of FS (full scale): Δxmax/xmax.
What is ADC test?
The curve-fit test is a global description of the ADC. This means that the errors measured by the test are averaged to give a general measurement of the ADC transfer function. The result of this test is a figure of merit called the number of effective bits for the ADC.
What causes linearity error?
Linearity error is the deviation of the sensor output curve from a specified straight line over a desired pressure range. This linearity error is also defined as non-linearity. The linearity error value is normally specified as a percentage of the specified pressure range.
How do you test ADC and DAC?
The two traditional methods used for SEE test of ADC/DAC use two converters: – the DUT is in series with the complementary device, DAC + ADC or ADC + DAC. This approach allows processing the data either with a numerical approach or, on the contrary, as analog signals.
What is the difference between INL and DNL?
A DNL error specification of less than or equal to 1LSB guarantees a monotonic transfer function with no missing codes. INL error is described as the deviation, in LSB or percent of full-scale range (FSR), of an actual transfer function from a straight line.
What does DNL stand for?
“DNL” is the acronym for Day-Night Average Sound Level, which represents the total accumulation of all sound energy, but spread out uniformly over a 24-hour period.
How to express the non linearity of an ADC?
If the ADC is ideal, the steps shown are perfectly superimposed on a line. Figure 2 shows an ADC with a slight non-linearity. To express the non-linearity in a standard way, manufacturers draw a line through the ADC transfer function, called the best fit line.
When to use LSB instead of LSB for ADC?
For integrated circuit design, when building an ADC as part of a signal processing chain or as a sub-block of a larger ADC it sometimes can make sense to to define the LSB differently ( L S B = F S R / ( 2 N − 1) ). The reason is that there are two conventions for ADCs depending on the code transition levels used.
Where does the first transition occur in an ADC?
The reason is that there are two conventions for ADCs depending on the code transition levels used. One is the so-called mid-tread convention where FSR/2 is right in the middle of a code and the first transition occurs at LSB/2. The other is the mid-riser convention where FSR/2 occurs at transition and the first transition occurs at LSB.
What are the parameters of an AD converter?
To explain the linearity parameters of an A/D converter, the plot below can overlay some example ADCs with an ideal 4 bits ADC. The 1/2 LSB option shows a ADC where the first transition point starts at a halve LSB in stead of 1 LSB. The plot can show five different kinds of ADC data: 5) Random ADC data: random errors.