Page 50 - Analog Circuit Design Art, Science, and Personalities

Samuel Wilensky

6. Reflections of a Dinosaur
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Sixty five million years ago, at the end of the Cretaceous period, the dinosaur
vanished from the earth. Some scientist believe that the disappearance was due
to the cataclysmic collision of a large body with Earth.
The explosive growth of digital technology is the cataclysmic event that has
threatened the analog designer with extinction. The linear circuit engineer has been
added to the list of endangered species. For the past twenty years the focus of the
engineering curriculum has shifted priority from analog to digital technology. The
result of this shift is that only a small fraction of recently trained engineers have the
analog design skills necessary to attack “real world” problems. The microprocessor
has revolutionized the area of measurement and control, but the transducers used to
measure and control temperature, pressure, and displacement are analog instruments.
Until sensors and actuators are available that can convert a physical parameter such
as temperature directly to digital information, the analog designer will still be in
demand.
‘4nalog design is a challenging field because most projects require the designer to
optimize a circuit by surrendering one performance parameter to enhance another.
As an old analog guru once said when comparing the analog and digital disciplines,
”Any idiot can count to one, but analog design requires the engineer to make intelli-
gent. trade-offs to optimize a circuit.” Analog design is not black or white as in
“ones” and “zeros”; analog design is shades of gray.
This essay contains the reflections, thoughts, and design philosophies of a nearly
extinct species of electrical engineer, the analog circuit designer. Digital technology
has reduced our population to a small fraction of those that existed twenty or thirty
years ago. This is unfortunate since the need for, and the challenge of, ‘analog design
is still with LIS. This chapter relates experiences 1 havc had as an electrical engineer
since I received my degree in June 1959. I hope these reflections will in some way
encourage and help the recently initiated and entertain those of you who remember
filament transformers and B+ power supplies.
My undergraduate electrical engineering education covered mainly vacuum tube
technology. but there were two “new“ areas that the department felt were of signifi-
cant enough importance to include in the curriculum. As a result, we received a
one-hour lecture on transistors and a one-hour lecture on crysistors. For those of
you who are unfamiliar with the crysistor, it is a superconducting magnetic memory
element that showed promise of revolutionizing the computer world.
It would have been difficult lo predict in 1960 that the vacuum tube would become
a relic of the past, transistor technology would rule, and the crysistor would com-
pletely disappear from the scene. Although the crysistors never made it, the discov-
ery of new low-temperature superconductors may give it a second chance.
Ir amazes me that most of the technology I work with today did not e\’en exist in

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