Low power complementary logic latch and rf divider

Abstract

A quadrature output high-frequency RF divide-by-two circuit includes a pair of differential complementary logic latches. The latches are interconnected to form a toggle flip-flop. Each latch includes a tracking cell and a locking cell. In a first embodiment, the locking cell includes two complementary logic inverters and two transmission gates. When the locking cell is locked, the two gates are enabled such that the locked (i.e., latched) signal passes through both transmission gates and both inverters. In one advantageous aspect, the tracking cell only involves two transmission gates. Due to the circuit topology, the first embodiment is operable from a low supply voltage at a high operating frequency while consuming a low amount of supply current. In a second and third embodiment, the tracking cell involves a pair of inverters. The sources of the transistors of the inverters are, however, coupled together thereby resulting in performance advantages over conventional circuits.