A technique for chaining the transistors in the layouts of static CMOS leaf cells is presented and analyzed. This new method is superior to existing techniques, since it can operate on a more general class of circuits and is very efficient. It is shown that the layout width of a CMOS leaf cell can be significantly reduced (nearly 40\% in the average case) by transistor chaining. Moreover, more than half of the switching functions of four variables have optimal CMOS circuit implementations with non-series/parallel topologies. Therefore, the use of non-series/parallel circuits can have a positive global impact on layout area and performance. The transistor chaining technique presented in this paper produces the optimal solution for 82% of the circuits tested, and has linear time complexity.
Citation:
Bradley S. Carlson, C.Y. Roger Chen, Dikran Meliksetian, "Transistor Chaining in CMOS Leaf Cells of Planar Topology," glsvlsi, pp.0194, 6th Great Lakes Symposium on VLSI, 1996