Analog-to-digital circuit converts an analog signal having continuous-time and continuous-amplitude to a discrete time and discrete-amplitude digital signal. A comparator is a vital block in any analog-to-digital circuit. The comparators play a crucial part in the analog to digital conversion. This paper puts forth the design of hysteresis comparator in 90-nm CMOS technology. The proposed comparator reduces the occurrence of noisy output and has high speed, in comparison to the conventional comparator. The circuit design and analysis has been done using Cadence.