Influence of Analog Input Circuits to DSP SAR ADC and its Optimization

With the growing market and the development of fast digital systems, the requirements for fast sampling of analog quantities also increase at the same time. To increase the speed of the control loops in fast systems, it is necessary to ensure fast sampling. However, this can bring other problems that are not visible at first glance. This paper deals with analysis of the internal circuits of the ADC and influence of this circuits to the external analog devices that are adjusting signals for the ADC such as operational amplifiers in various configurations. Finally, this paper presents guide to proper design input circuits to minimize distortion of the sampled signal by the ADC circuits.