Reduced implementation of D-type DET flip-flops

One of the main disadvantages of using D-type double-edge triggered flip-flops (DET-FFs) in VLSI system design is the number of transistors required. Two new DET-FF circuits (one static, the other dynamic) are proposed in which the number of transistors is reduced to a number similar to that for classic single-edge triggered flip-flops (SET-FFs). Both new circuits not only behave correctly when operated at high frequency but also offer a good level of immunity to metastability problems (static) and race problems (dynamic), as well as presenting a simple straightforward layout. These considerations offer wider practical and economic applications for the use of DET-FFs in VLSI system design