Design and Analysis of CMOS Frequency Dividers With Wide Input Locking Ranges

A millimeter-wave (MMW) frequency synthesizer needs a low-power frequency divider (FD) with a wide input locking range to ensure reliability and lower power operation. In this paper, the design and analysis of low-power wide locking range MMW FDs are presented. Proposed are two divide-by-2 (D2) and divide-by-4 (D4) FDs that achieve the widest locking range reported to date by using a dual-mixing technique. Both FDs are fabricated in 90-nm CMOS and are demonstrated to achieve very wide input locking ranges without any tuning mechanism. At an input power of 0 dBm, the D2 FD has a locking range of 51–74 GHz, and that of the D4 FD is 82.5–89 GHz. The power consumption is only 3 mW for both the D2 FD and the D4 FD, from a 0.5 V supply. The proposed D2 and D4 FDs may facilitate incorporation into a product of a MMW phase-locked loop that is smaller, consumes less power, and is more reliable than the conventional approach.