Chapter 1
Introduction
In the modern integrated circuit (IC) design the objective is to increase operation
speed (maximum frequency) and decrease power consumption. The maximum
frequency of an IC is a function of the longest encountered delay in its different
parts. Signal delay can be reduced by increasing the transistor density, but to
increase transistor density in an IC, dimensions of the CMOS transistors in the
IC must be scaled. Decreasing power consumption also demands reducing CMOS
transistors dimensions. As we know, Moore’s law predicts that the number of
transistors on an inexpensive IC doubles every two years. For example, the Intel
80486 introduced in 1989 was manufactured using 0.8μm CMOS technology and
had a the maximum clock speed of 133MHz. Today’s modern processors, such
as the Intel Core 2, are manufactured using 65nm technology or less, and the
maximum frequency can be more than 3.20 GHz.