Comparators play an important role in designing of SAR ADC. In this paper we achieve the required performance of SAR ADC at minimum power usage. Using of comparators will reduce the power and noise, Dynamic latch circuit used in comparator increases the speed. The differential amplifier is also discussed. Here we will get to know about Ramp ADC and also about various DAC’s like M-DAC and AUX-DAC. The time-interleaving technique is the design technique that is used to increase the speed.