A graph-based signal flow direction assignment method for CMOS circuits

Signal flow direction (SFD) assignment for CMOS transistors plays an important role in many VLSI CAD tools. The authors present a new graph-based SFD assignment method. It has a linear time performance for circuits that can be parallel-serial reduced. For circuits which are not completely reduced, their sizes are usually very small and an exhaustive search algorithm can assign SFDs quickly. SFD assignment is guided by a nonheuristic rule which provides a simple universal view of different circuit structures. The SFDs derived by this method have a favorable containment property. Experimental results show that the method is very efficient compared to existing approaches.<
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