One of the difficulties in achieving high performance in VLSI design today has been the development of low power consumption requirements for the various applications and electronic products. As a result, many technologies have been developed to reduce power consumption, and one of them is the sleep transistor technique. In this paper, we compare two different phase frequency detector circuits for phase locked loop with sleep transistor technique. The phase frequency detector is implemented in cadence virtuoso using the library GPDK090 of 90 nm CMOS Technology. It is observed that, by applying the power optimization technique there is reduction in power consumption thereby seeing an improvement of 29%.