TOPIC 6
INTEGRATED CIRCUIT
How are Integrated Circuits Made?
An integrated circuit or IC is basically the assembly of
electronic components fabricated on a semiconductor
material as a unit. There are different techniques used to
design and construct integrated circuits. In today's world,
integrated circuits are used in almost all electronic
equipment.
Integrated Circuits
An Integrated circuit (IC, microchip, or chip) is an electronic
circuit made up of small semiconductor devices and other
electronic components that are manufactured on a
semiconductor material.
Integrated Circuits
The integration of a large number of transistors on a single
chip was a great achievement. It was only possible after a
large number of experiments, and then it was found that
semiconductor devices could perform the functions of
vacuum tubes. The first integrated chip was designed by Jack
S. Kilby at Texas Instruments in 1958.
Advantages of ICs
The discovery of integrated circuits was a great advance in
the field of electronics because integrated circuits were
much more reliable, capable, and cheaper than discrete
circuits.
Advantages of ICs
The space taken up by electronic components is small as all
components are printed as a single unit and much less
material is required.
Power consumption is another advantage of integrated
circuits because the components are very small in size and
work as a unit.
Designing
There are certain circuit design and logic techniques that are
used to design an integrated circuit. There are two categories
of IC design which are:
Digital design
Analog Design
Designing
Microprocessors, memories (RAM, ROM) . are designed by
Digital IC design method. Digital designing ensures that the
circuits are correct and the circuit density is at maximum. The
overall efficiency of the circuit is very high.
Designing
The analog design method is used to design oscillators,
filters, line regulators, op amps, and phase locked loops.
The analog design is used when perfect gain, power
dissipation, and resistance are required.
Analog Design
In Analog Design, circuit simulation tools are used to design
the ICs with high efficiency and make complex calculations.
The first circuit simulator that was used for this purpose was
called "SPICE."
Analog Design
If there are any mistakes in the design cycle, the circuit
simulation tools find them so that they can be fixed before
the fabrication process. Also other factors such as
temperature and doping concentration can be monitored.
Diode
A diode is a device made of a semiconductor material, which
has two terminals or electrodes (diode), which act as an on
and off switch. When the diode is "on", it acts as a short
circuit and everything happens. When it is "off", it acts as an
open circuit and does not pass current.
The two terminals are different and are marked as plus and
minus in figure 1. If the polarity of the applied voltage
matches that of the diode (forward bias), then the diode is
“turned on”.
When the polarity of the applied voltage is opposite (reverse
bias), it turns off.