Page 174 - Bebop to The Boolean Boogie An Unconventional Guide to Electronics Fundamentals, Components, and Processes

Integrated Circuits (ICs) 155

Integrated Circuits versus Discrete Components
The tracks linking components inside an integrated circuit have widths
measured in fractions of a millionth of a meter and lengths measured in milli-
meters. By comparison, the tracks linking components on a circuit board are
orders of magnitude wider and have lengths measured in tens of centimeters.
Thus, the transistors used to drive tracks inside an integrated circuit can be
much smaller than those used to drive their circuit board equivalents, and
smaller transistors use less power. Additionally, signals take a finite time to
propagate down a track, so the shorter the track, the faster the signal.
A single integrated circuit can contain tens (sometimes hundreds) of
millions of transistors. A similar design based on discrete components would be
tremendously more expensive in terms of price, size, operating speed, power
requirements, and the time and effort required to design and manufacture the
system. Additionally, every solder joint on a circuit board is a potential source
of failure, which affects the reliability of the design. Integrated circuits reduce
the number of solder joints and hence improve the reliability of the system.

In the past, an electronic system was typically composed of a number of
integrated circuits, each with its own particular function (say a microprocessor,
a communications function, some memory devices, etc.). For many of today's
high-end applications, however, electronics engineers are combining all of these
functions on a single device, which may be referred to as a systemon-ckp (SoC).

Different Types of ICs

The first integrated circuit-a simple phase shift oscillator-was constructed
in 1958." Since that time, a plethora of different device types have appeared
on the scene. There are far too many different integrated circuit types for us to
cover in this book, but some of the main categories-along with their approxi-
mate dates of introduction-are shown in Figure 14-18.12

11 The first integrated circuits typically contained around six transistors. By the latter half of the
1960s, devices containing around 100 transistors were reasonably typical.
12 The white portions of the timeline bars in this figure indicate that although early inc- ernat ions
of these technologies may have been available, they perhaps hadn't been enthusiastically
received during this period. For example, Xilinx introduced the world's first FPGA as early
as 1984, but many design engineers didn't really become interested in these little rapscallions
until the late 1980s.