Analog to Digital converters (ADC) are main design blocks for high efficiency medical applications. This paper represents a low power SAR ADC that uses a monotonic switching procedure in which switching occurs in one direction only thus switching energy reduces. As compared to conventional converter capacitance is reduced and Common mode voltage is also suppressed in the proposed method. So, dynamic latch comparator is being used to reduce the offset caused due to variation in the common mode voltage. A reliable low-distortion CMOS bootstrapped sampling switch is used. This work proposed asynchronous control logic technique to design low power, A/D converter that can be used for biomedical applications and does not employ any component trimming or adjustment. We achieved 1mW power dissipation for the proposed circuit. This architecture is simulated at 180nm technology using Cadence tool at 1.8Vsupply voltage. © 2016 IEEE.