covered under subject of Electrical Enginerring Workshop in GTU

3. Integrated Circuits are usually called ICs
and popularly known as a silicon chip, computer
chip or microchip.

4.  Integrated Circuit, tiny electronic circuit used to
perform a specific electronic function, such as
amplification.
 It is usually combined with other components to
form a more complex system.

5. Electronic Components?
Miniaturized Active Devices:
1. Transistors
2. Diodes
Miniaturized Passive Devices:
1. Capacitors
2. Resistors
-> It is formed as a single unit by diffusing impurities into single-crystal
silicon, which then serves as a semiconductor material.

6.  Several hundred identical integrated
circuits (ICs) are made at a time on a
thin wafer several centimeters wide,
and the wafer is subsequently sliced into
individual ICs called chips.

8. It seems that the integrated circuit was
destined to be invented. Two separate
inventors, unaware of each other's activities,
invented almost identical integrated circuits or
ICs at nearly the same time.

9. As with many inventions, two people had the idea for an
integrated circuit at almost the same time. Transistors had
become commonplace in everything from radios to phones
to computers, and now manufacturers wanted something
even better. Sure, transistors were smaller than vacuum
tubes, but for some of the newest electronics, they weren't
small enough.

10. But there was a limit on how small you could make each
transistor, since after it was made it had to be connected to
wires and other electronics. The transistors were already at
the limit of what steady hands and tiny tweezers could
handle. So, scientists wanted to make a whole circuit -- the
transistors, the wires, everything else they needed -- in a
single blow. If they could create a miniature circuit in just
one step, all the parts could be made much smaller.

11. One day in late July, Jack Kilby was sitting alone at Texas
Instruments. He had been hired only a couple of months earlier
and so he wasn't able to take vacation time when practically
everyone else did. The halls were deserted, and he had lots of time
to think. It suddenly occurred to him that all parts of a circuit, not
just the transistor, could be made out of silicon. At the time,
nobody was making capacitors or resistors out of semiconductors.
If it could be done then the entire circuit could be built out of a
single crystal -- making it smaller and much easier to produce.
Kilby's boss liked the idea, and told him to get to work. By
September 12, Kilby had built a working model, and on February
6, Texas Instruments filed a patent. Their first "Solid Circuit" the
size of a pencil point, was shown off for the first time in March.

14. In January of 1959, Robert Noyce was working at the small Fairchild
Semiconductor startup company. He also realized a whole circuit could
be made on a single chip. While Kilby had hammered out the details of
making individual components, Noyce thought of a much better way to
connect the parts. That spring, Fairchild began a push to build what they
called "unitary circuits" and they also applied for a patent on the idea.
Knowing that TI had already filed a patent on something similar, Fairchild
wrote out a highly detailed application, hoping that it wouldn't infringe
on TI 's similar device.

15. ALL THAT DETAIL PAID OFF. ON APRIL 25, 1961, THE PATENT
OFFICE AWARDED THE FIRST PATENT FOR AN INTEGRATED
CIRCUIT TO ROBERT NOYCE WHILE KILBY'S APPLICATION WAS
STILL BEING ANALYZED. TODAY, BOTH MEN ARE ACKNOWLEDGED
AS HAVING INDEPENDENTLY CONCEIVED OF THE IDEA.

17. In the early days of integrated circuits, only a few
transistors could be placed on a chip, as the scale
used was large because of the contemporary
technology, and manufacturing yields were low by
today's standards. As the degree of integration was
small, the design was done easily. Over time,
millions, and today billions, of transistors could be
placed on one chip, and to make a good design
became a task to be planned thoroughly. This gave
rise to new design methods.

18. Integrated circuits are often classified by the number of transistors and
other electronic components they contain:
 SSI (small-scale integration): Up to 100 electronic components per
chip
 MSI (medium-scale integration): From 100 to 3,000 electronic
components per chip
 LSI (large-scale integration): From 3,000 to 100,000 electronic
components per chip
 VLSI (very large-scale integration): From 100,000 to 1,000,000
electronic components per chip
 ULSI (ultra large-scale integration): More than 1 million electronic
components per chip

20. Integrated circuits can be classified
into analog, digital and mixed signal (both analog and
digital on the same chip).

21. Digital integrated circuits can contain anything from one to millions
of logic gates, flip-flops, multiplexers, and other circuits in a few square
millimeters. The small size of these circuits allows high speed, low
power dissipation, and reduced manufacturing cost compared with
board-level integration. These digital ICs,
typically microprocessors, DSPs, and micro controllers, work using
binary mathematics to process "one" and "zero" signals.

22. Analog ICs, such as sensors, power management circuits,
and operational amplifiers, work by processing continuous signals.
They perform functions like amplification, active
filtering, demodulation, and mixing. Analog ICs ease the burden on
circuit designers by having expertly designed analog circuits available
instead of designing a difficult analog circuit from scratch.

23. ICs can also combine analog and digital circuits on a single chip to
create functions such as A/D converters and D/A converters. Such
circuits offer smaller size and lower cost, but must carefully account
for signal interference.

25. THE INTEGRATED CIRCUITS OFFER A NUMBER OF ADVANTAGES
OVER THOSE MADE BY INTERCONNECTING DISCRETE
COMPONENTS. THESE ARE SUMMARIZED AS FOLLOWS:
1. Extremely small size—thousands times smaller than discrete circuit. It is
because of fabrication of various circuit elements in a single chip of semi-
conductor material.
2. Very small weight owing to miniaturized circuit.
3. Very low cost because of simultaneous production of hundreds of similar
circuits on a small semiconductor wafer. Owing to mass production
an IC costs as much as an individual transistor.
4. More reliable because of elimination of soldered joints and need for
fewer inter-connections.
5. Low power consumption because of their smaller size.
6. Easy replacement as it is more economical to replace them than to repair
them.

26. THE INTEGRATED CIRCUITS OFFER A NUMBER OF ADVANTAGES OVER THOSE MADE BY
INTERCONNECTING DISCRETE COMPONENTS. THESE ARE SUMMARIZED AS FOLLOWS:
7. Increased operating speeds because of absence of parasitic capacitance
effect.
8. Close matching of components and temperature coefficients because of
bulk produc¬tion in batches.
9. Improved functional performance as more complex circuits can be
fabricated for achieving better characteristics.
10. Greater ability of operating at extreme temperatures.
11. Suitable for small signal operation because of no chance of stray
electrical pickup as various components of an IC are located very close to
each other on a silicon wafer.
12. No component project above the chip surface in an IC as all the
components are formed within the chip.

28. THE INTEGRATED CIRCUITS HAVE FEW LIMITATIONS ALSO,
AS LISTED BELOW :
1. In an IC the various components are part of a small semi-conductor chip
and the individual component or components cannot be removed or
replaced, therefore, if any component in an IC fails, the whole IC has to be
replaced by the new one.
2. Limited power rating as it is not possible to manufacture high power (say
greater than 10 Watt) ICs.
3. Need of connecting inductors and transformers exterior to the semi-
conductor chip as it is not possible to fabricate inductors and
transformers on the semi-conductor chip surface.
4. Operations at low voltage as ICs function at fairly low voltage.
5. Quite delicate in handling as these cannot withstand rough handling or
excessive heat.

29. THE INTEGRATED CIRCUITS HAVE FEW LIMITATIONS ALSO, AS LISTED BELOW
:
6. Need of connecting capacitor exterior to the semi-conductor chip as it is
neither convenient nor economical to fabricate capacitances exceeding
30 pff Therefore, for higher values of capacitance, discrete components
exterior to IC chip are connected.
7. High grade P-N-P assembly is not possible.
8. Low temperature coefficient is difficult to be achieved.
9. Difficult to fabricate an IC with low noise.
10. Large value of saturation resistance of transistors.
11. Voltage dependence of resistors and capacitors.
12. The diffusion processes and other related procedures used in the
fabrication process are not good enough to permit a precise control of
the parameter values for the circuit elements. However, control of the
ratios is at a sufficiently acceptable level.