What is the technique involved in ADC conversion?
An ADC converts a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal. The conversion involves quantization of the input, so it necessarily introduces a small amount of error or noise.
How is DNL calculated for ADC?
It is defined as follows: DNL = |[(VD+1- VD)/VLSB-IDEAL – 1] | , where 0 < D < 2N – 2. VD is the physical value corresponding to the digital output code D, N is the ADC resolution, and VLSB-IDEAL is the ideal spacing for two adjacent digital codes.
How do you test an ADC?
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 DAC calibration?
Calibration is done in the linear region of the DAC, which is where the offset and gain error are measured. The data sheet specifies the codes at which these measurements are taken. The easiest way to do the calibration is by using a two-point approach, taking points on either end of the linear region.
How do you calculate calibration offset?
The gain and offset error will be calculated using the equation of a straight line y = mx + b, where m is the slope of the line and b is the offset. The gain error can be calculated as the slope of the actual ADC output divided by the slope of the ideal ADC output.
Which is the fastest a D convertion techniques?
flash conversion
Parallel A/D conversion (sometimes called flash conversion) is the fastest technique available and the simplest to understand. However, its practicality is limited to small numbers of bits, since it requires 2N – 1 comparator circuits in order to produce an N-bit digital output.
How do you convert raw voltage to ADC?
ADC has a resolution of one part in 4,096, where 212 = 4,096. Thus, a 12-bit ADC with a maximum input of 10 VDC can resolve the measurement into 10 VDC/4096 = 0.00244 VDC = 2.44 mV. Similarly, for the same 0 to 10 VDC range, a 16-bit ADC resolution is 10/216 = 10/65,536 = 0.153 mV.
What is the difference between INL and DNL?
DNL is a function of each ADC’s particular architecture. It is not possible to remove its effects with calibration. INL – Integral Non-Linearity: DNL errors accumulate to produce a total Integral Non-Linearity (INL).
How does DAC calculate DNL and INL?
For example, considering the transition from 001 to 010, we get an output step of 2.5I ✖ RL. The deviation of this step from one LSb value is 2.5I ✖ RL – I ✖ RL = 1.5I ✖ RL. Hence, the DNL of this transition is 1.5 LSb.
How is ADC accuracy calculated?
It is expressed as the number of bits output by the ADC. Therefore, an ADC which converts the analog signal to a 12-bit digital value has a resolution of 12 bits. -1. With a 3.3 V reference voltage, the resolution is 3.3/212 = 3.3/4096 = 0.805 (mV).
What is the accuracy of AD a converter?
Remember the bottom LSBs/bits are flickering because of the noise in the ADC! This also means the converter has an accuracy of ±6.12 mV or 0.0612%. Additionally, this implies that for a 1.00000 V input applied to the converter, the output can be between 0.99388 V and 1.00612 V.
What are the three techniques involved in conversion?
The conversion involves three techniques: line coding, block coding, and scrambling.
How do you calculate input voltage for ADC?
How is DAC resolution calculated?
For example, an 8-bit DAC that generates a maximum output voltage of 5 volts has a step size or resolution of (5V / 2 8 ) = 19.5 mV. Sometimes, the resolution is stated in the percentage value. For the 8-bit DAC, the percent resolution is (1 / 2 8 ) x 100 = 0.39%.
What is leakage current in ADC?
The input leakage is a DC current that flows into or out of the data converter input pins. This current results from internal ESD protection structures and other parasitic structures. This current can be modeled as a DC current source on both ADC inputs, and is typically in the nanoamp to microamp level.