Design of high speed CMOS prescaler

Abstract

A high-speed divide-by-2 prescaler is designed in a 0.8 um CMOS. New ECL-like D flip-flop is proposed having source-folded diode clamping. Significant amount of speed up can be obtained using source-folded diode with proper sizing ratio of transistors, and lower power consumption can be obtained by designing low power D flip-flop and removing additional input-amplifying buffer. The simulated maximum input frequency of the suggested prescaler reaches up to 3.15 GHz with only 5 mA and 1.8 GHz with 1.6 mA at 3.3 V.