The present invention presents a mobile station of a wireless communications system such that when the mobile station is in idle mode (i.e., listening to a paging channel periodically, but otherwise taking no action), the control processor commands the mobile station to enter into sleep mode to minimize power consumption. During sleep mode, the high-frequency reference clock and thus all high-frequency clocks derived from it are turned off. Only a low-frequency clock remains operating at all times to clock the sleep logic.