1-32
Q32. On DIP and flat-pack ICs viewed from the top, pin 1 is located on which side of the reference
mark?
Q33. DIP and flat-pack pins are numbered consecutively in what direction?
Q34. DIP and flat-pack pins are numbered consecutively in what direction?
Q35. Viewed from the bottom, TO-5 pins are counted in what direction?
Q36. The numbers and letters on ICs and schematics serve what purpose?
MICROELECTRONIC SYSTEM DESIGN CONCEPTS
You should understand the terminology used in microelectronics to become an effective and
knowledgeable technician. You should be familiar with packaging concepts from a maintenance
standpoint and be able to recognize the different types of assemblies. You should also know the electrical
and environmental factors that can affect microelectronic circuits. In the next section of this topic we will
define and discuss each of these areas.
TERMINOLOGY
As in any special electronics field, microelectronics terms and definitions are used to clarify
communications. This is done so that everyone involved in microelectronics work has the same
knowledge of the field. You can imagine how much trouble you would have remembering 10 or more
different names and definitions for a resistor. If standardization didn't exist for the new terminology, you
would have far more trouble understanding microelectronics. To standardize terminology in
microelectronics, the Navy has adopted several definitions with which you should become familiar. These
definitions will be presented in this section.
Microelectronics
Microelectronics is that area of electronics technology associated with electronics systems built from
extremely small electronic parts or elements. Most of today's computers, weapons systems, navigation
systems, communications systems, and radar systems make extensive use of microelectronics technology.
Microcircuit
A microcircuit is not what the old-time technician would recognize as an electronic circuit. The old-
timer would no longer see the familiar discrete parts (individual resistors, capacitors, inductors,
transistors, and so forth). Microelectronic circuits, as discussed earlier, are complete circuits mounted on a
substrate (integrated circuit). The process of fabricating microelectronic circuits is essentially one of
building discrete component characteristics either into or onto a single substrate. This is far different from
soldering resistors, capacitors, transistors, inductors, and other discrete components into place with wires
and lugs. The component characteristics built into microcircuits are referred to as ELEMENTS rather than
discrete components. Microcircuits have a high number of these elements per substrate compared to a
circuit with discrete components of the same relative size. As a matter of fact, microelectronic circuits
often contain thousands of times the number of discrete components. The term HIGH EQUIVALENT
CIRCUIT DENSITY is a description of this element-to-discrete part relationship. For example, suppose
you have a circuit with 1,000 discrete components mounted on a chassis which is 8
10
2 inches. The
equivalent circuit in microelectronics might be built into or onto a single substrate which is only 3/8
1
1/4 inch. The 1,000 elements of the microcircuit would be very close to each other (high density) by
