Logic circuit design

The aim of this article is to present the main principles of hardware logic operators, both combinational and sequential, used in electronic and computer systems. The essential characteristics of CMOS technology, and of static and dynamic circuitry, are described to highlight the compromises made between speed, area and power consumption when designing different types of circuit: ASIC circuits (specialized for one application), programmable logic circuits, in particular FPGAs, microprocessors and memories.

If integration density continues to grow exponentially according to Moore's Law, energy issues (power dissipation and consumption for battery-powered systems) become inescapable.

The fundamentals of static memory (SRAM) and dynamic memory (DRAM) are presented, along with the main features of programmable logic circuits and their evolution. The most popular of these, FPGAs, can now be used to build complete systems-on-a-chip integrating processors, memories and specialized interface circuits. For ASICs, examples illustrate how optimization problems linked to the need to reduce power dissipation and energy consumption come into play at different levels to take into account the characteristics of the latest generations of CMOS technology.

A table of acronyms and a table of symbols used are presented at the end of the article.