| High-level model based calibration technique design for SAR ADC |
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| Authors |
| | Skripnichenko M.N. |
| Date of publication |
| | 2020 |
| DOI |
| | 10.31114/2078-7707-2020-3-114-119 |
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| Abstract |
| | This paper presents a method of algorithm developing and debugging for mixed signal devices using a Python mathematical model. A successive approximation register ADC is used as the mixed signal device.
A splitted capacitor array with small numbers of sampling switches and capacitors of reasonable sizes is used in mathematical model.
To simplify calculations the operator method, that replaces differential-integral expressions with algebraic ones, is used.
The basis for the mathematical model is the dependence of the voltage at the input of the comparator on the matrix side depending change in switch states of the keys. Value of the function of uniform distribution from zero to 0.01 of the smallest capacitor in the section was randomly added or subtracted to each capacitor to simulate the dispersion of capacitors. The noise model is an additive source at the input of the comparator. As result, there is a mathematical model of SAR ADC with event-driven architecture.
The events at which the circuit state changes are changing of states in sampling switches K0 and bit switches.
One of the reasons for the deterioration of the dynamic characteristics of the ADC is mismatch in capacitor array during chip fabrication. To improve the characteristics, algorithm that takes into account capacitors mismatch is used.
Such algorithm shows efficiency in the conditions of capacitor mismatch and comparator input noise.
With this algorithm signal to noise ratio is increased by 7.3 dB, which is equivalent to 1.2 effective bit.
Spurious-free dynamic range increases by 16.8 dB.
Using the mathematical model when designing and debugging calibration algorithms allows you to speed up these processes. |
| Keywords |
| | SAR ADC, ADC simulation, SAR ADC calibration, ADC math model. |
| Library reference |
| | Skripnichenko M.N. High-level model based calibration technique design for SAR ADC // Problems of Perspective Micro- and Nanoelectronic Systems Development - 2020. Issue 3. P. 114-119. doi:10.31114/2078-7707-2020-3-114-119 |
| URL of paper |
| | http://www.mes-conference.ru/data/year2020/pdf/D080.pdf |
