ABSTRACT

Complementary metal oxide semiconductor (CMOS) very large scale integration (VLSI) logic circuits can be mainly classified into two main categories: static logic circuits and dynamic logic circuits. The term VLSI refers to a technology through which it is possible to implement large circuits consisting of up to or more than a million transistors on semiconductor wafers, primarily silicon. CMOS logic circuits are made up of n-channel and p-channel metal oxide semiconductor field effect transistors. Semiconductor memory arrays are widely used in many VLSI subsystems, including microprocessors and other digital systems. More than half of the real estate in many state-of-the-art microprocessors is devoted to cache memories, which are essentially memory arrays. Static random access memory cells require 4–6 transistors per cell and need 4–5 lines connecting to each cell including power, ground, bit lines, and word lines. The power reduction techniques at the circuit level are quite limited when compared with the other techniques at higher abstraction levels.