An All-Digital Phase-Locked Loop (ADPLL)-Based Clock Recovery Circuit

A new algorithm for all-digital phase-locked loops (ADPLL) with fast acquisition and large pulling range is presented in this paper. Based on the proposed algorithm, portable cell-based implementations for clock recovery with functions of a frequency synthesizer and on-chip clock generator are completed by standard cell. These modules have been designed and verified on a 0.6m CMOS process. Test results are summarized as follows: 1) the proposed ADPLL can satisfy full locked bandwidth and fast acquisition within one data transition; 2) the on-chip clock generator can generate any target clock rate f clock; and 3) the function of nonreturn-to-zero clock recovery has a maximum f clock/4 recovering capability with a locking range of ( input input/2), where input is the input period.