High-speed wide-range true-single-phase-clock cmos dual modulus prescaler

This manuscript presents two novel low-power high-speed true-single-phase-clock (TSPC) prescalers with division ratios of 2/3 and 4/5, respectively, in a standard 90-nm CMOS technology. The logic gates incorporated between the D-flip-flops (DFFs) of a conventional 2/3 prescaler are modified to reduce the propagation delay and hence increase the maximum operating frequency. The measurement results show that the proposed divide-by-2/3 and divide-by-4/5 prescalers can operate up to 17 GHz and 15.3 GHz, respectively, which increase by 5.4 GHz and 4.3 GHz compared with conventional TSPC prescalers. The power of the proposed divide-by-2/3 prescaler is 0.67 mW and 0.92 mW, and 0.87 mW and 1.06 mW for the proposed divide-by-4/5 prescaler. The chip occupies an area of 20 × 35 µm² and 20 × 50 µm² for the proposed divide-by-2/3 and divide-by-4/5 prescalers.