Integrated Circuits
Advantages
of Integrated Circuits
The major advantages of integrated
circuits over those made by interconnecting discrete components are as follows
:
Extremely small size – Thousands
times smaller than discrete circuits. It is because of fabrication of various
circuit elements in a single chip of semiconductor material.
Very small weight owing to
miniaturised circuit.
Very low cost because of
simultaneous production of hundreds of similar circuits on a small
semiconductor wafer. Owing to mass production of an IC costs as much as an
individual transistor.
More reliable because of
elimination of soldered joints and need for fewer interconnections.
Lower power consumption because of
their smaller size.
Easy replacement as it is more
economical to replace them than to repair them.
Increased operating speed because
of absence of parasitic capacitance effect.
Close matching of components and
temperature coefficients because of bulk production in batches.
Improved functional performance as
more complex circuits can be fabricated for achieving better characteristics.
Greater ability of operating at
extreme temperatures.
Suitable for small signal operation
because of no chance of stray electrical pickup as various components of an INC
are located very close to each other on a silicon wafer.
No component project above the chip
surface in an INC as all the components are formed within the chip.
Disadvantages
of Integrated Circuits
The major disadvantages of integrated
circuits over those made by interconnecting discrete components are as follows
:
1) In an IC the various components
are part of a small semiconductor 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 a new one.
2) Limited power rating as it is
not possible to manufacture high power (say greater than 10 W) ICs.
3) Need of connecting inductors and
transformers exterior to the semiconductor chip as it is not possible to
fabricate inductor and transformers on the semiconductor chip surface.
4) Operation at low voltage as ICs
function at fairly low voltage.Quite delicate in handling as these cannot
withstand rough handling or excessive heat.
5) Need of connecting capacitor
exterior to the semiconductor chip as it is neither convenient nor economical
to fabricate capacitances exceeding 30pF. Therefore, for higher values of
capacitance, discrete components exterior to IC chip are connected.
6) High grade P-N-P assembly is not
possible.
7) Low temperature coefficient is
difficult to be achieved.
8) Large value of saturation
resistance of transistors.
9) Voltage dependence of resistor
and capacitors.
10) 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.
The
Limitations of an Integrated Circuit:
1)A single integrated circuit
can only work when it is connected to the corresponding peripheral
components and is provided power source.
2) There are many transistors but
few inductors, resistors and capacitors in integrated circuits, because making
those inductors need to use large areas of silicon which result in high cost.
3) Once the integrated
circuit is manufactured, the internal circuit couldn’t be changed, unlike
the discrete component circuit. Thus, the whole integrated circuit can only be
replaced when one of the components in the integrated circuit is damaged.
4) The integrated circuit can't be
used alone, which need to be combined with discrete components and
form a practical circuit.
No technological advancement ever
comes without a downside. Integrated circuits have limitations that engineers
must consider when designing an electronic device or system.While some
components are easy to fabricate onto chips, other components defy the IC
manufacturing process. Inductors, except for components with extremely low
values (in the nanohenry range), constitute a prime example. Devices using ICs
must generally be designed to work with discrete inductors (coils) external to
the ICs themselves. This constraint need not pose a problem, however.
Resistance-capacitance (RC) circuits can do
Scale
of Integration – SSI, MSI, LSI, VLSI, ULSI
IC design has evolved from single
transistors to SSI (small-scale integration), to MSI (medium-scale
integration), to LSI (large-scale integration) and to VLSI (Very Large Scale
Integration). An IC is normally classified by either by the number of
transistors it has, such as LSI, VLSI, and so on, or by the size of the
transistor (covered in Chapter 4). Typical pitch sizes are 1, 1.5 and 2 mm (2
micros). Table 1.1 outlines the typical applications for the different
classifications. Table 1.1 Design classifications. Type No. of transistors
Typical applications SSI 1-100 Logic gates, op-amps, linear applications. MSI 100-1
000 Registers, filters, and so on. LSI 1 000-100 000 8-bit
microprocessors, up to 64 kbit ROMs and RAMs, Analogue-to-Digital converters,
and so on VLSI 100 000-500 000 16/32-bit microprocessors, up to 256
kbit ROMs/RAMs, signal processors. ULSI† >500 000 64-bit microprocessors, 8
Mbit RAMs, real-time and image processors. GSI* >10 000 000 64 Mbit
RAMs, integrated multi-processors. † ULSI represents ultra-large scale
integration * GSI represents gigantic scale integration.
first IC was invented around 1959
by Jack Kilby.
There after integrity has come like
SSI,MSI,LSI and VLSI
In SSI(Small Scale Integration )
—10–100 transistors/chip or 3 - 30 gates /chip(logic gates, flip flops)
In MSI(Medium Scale Integration ) —100–1000 transistors/chip
or 30 - 300 gates /chip(counters, multiplexers, registers)
In LSI(Large Scale Integration ) —1000–10,000
transistors/chip or 300 - 3000 gates /chip(8 bit processors)
In VLSI( Very Large Scale
Integration ) —10,000–1,00,000 transistors/chip or more than 3000 gates
/chip.(16 bit and 32 bit processors)
In ULSI( Ultra Large Scale
Integration ) —10power 6 –10 power 7 transistors/chip(smart sensors, VR reality
modules)
Moore's
Law
Moore's Law asserts that the number
of transistors on a microchip doubles every two years, though the cost of
computers is halved. In other words, we can expect that the speed and
capability of our computers will increase every couple of years; and we will
pay less for them. Another tenet of Moore's Law is that this growth in the
microprocessor industry is Exponential meaning that it will expand
steadily and rapidly over time. Understanding Moore's Law
In 1965, Gordon E. Moore—the
co-founder of Intel (NASDAQ: INTC)—postulated in a magazine article that the
number of transistors that can be packed into a given unit of space
will double about every two years. (Now, however, doubling of
installed transistors on silicon chips occurs closer to every 18 months instead
of every two years.) Gordon Moore did not call his observation "Moore's
Law," nor did he set out to create a "law." Moore made that
statement based on noticing emerging trends in chip manufacturing at Intel.
Moore's insight became a prediction, which in turn became the golden rule known
as Moore's Law.
Moore's Law proved to be true. For
decades following Gordon Moore's original observation, Moore's Law has guided
the semiconductor industry in long-term planning and setting targets for
research and development (R&D). Moore's Law has been a driving force of
technological and social change, productivity, and economic growth that are
hallmarks of the late-twentieth and early twenty-first centuries. Moore's
Law—Nearly 60 Years, Still Strong. More than 50 years later, we feel the
lasting impact and benefits of Moore's Law in many ways .Moore's Law implies
that computers, machines that run on computers, and computing power all become
smaller and faster with time, as transistors on integrated circuits become
more efficient. Chips and transistors are microscopic structures that contain
carbon and silicon molecules, which are aligned perfectly to move electricity
along the circuit faster. The faster a microchip processes electrical signals,
the more efficient a computer becomes. Costs of these higher-powered computers
eventually decrease by about 30% per year because of lower labor
costs. Practically every facet of a high-tech society benefits from Moore's Law
in action. Mobile devices, such as smartphones and computer tablets would not
work without tiny processors; neither would video games, spreadsheets, accurate
weather forecasts, and global positioning systems (GPS).Moreover, smaller
and faster computers improve transportation, health care, education, and energy
production—to name but a few of the industries that have progressed because of
the power of computer chips. [Important: Moore's Law may reach its natural end
in the 2020s.]Experts agree that computers should reach the physical limits of
Moore's Law at some point in the 2020s. The high temperatures of transistors
eventually would make it impossible to create smaller circuits. This is because
cooling down the transistors takes more energy than the amount of energy that
already passes through the transistors. In a 2005 interview, Moore himself
admitted that his law “can’t continue forever. It is the nature of
exponential functions," he said, "they eventually hit a wall.
"Shrinking transistors have powered advances in computing for more than
half a century, but soon engineers and scientists must find other ways to make
computers more capable. Instead of physical processes, applications and
software may help improve the speed and efficiency of computers. Cloud
computing, wireless communication, the Internet of Things, and quantum
physics all may play a role in the future of computer tech innovation. The
vision of an endlessly empowered and interconnected future brings both
challenges and benefits. Privacy and security threats are growing concerns. In
the long run, however, the advantages of ever-smarter computing technology
ultimately can help keep us healthier, safer, and productive. Examples of
Moore's Law abound everywhere we turn today. For instance, you likely have
experienced the need to purchase a new computer or phone more often than you
thought—say every two-to-four years—either because it was too slow, would not
run a new application well, or for other reasons. This is a phenomenon of
Moore's Law that we all know well. Perhaps, however, Moore's Law—or its
impending death—is most painfully present at the chip manufacturers themselves;
as these companies are saddled, not only with making our computing chips but
building them with increasing capacity against the physical odds.
Even Intel is competing with itself and its industry to create what
ultimately may not be possible. in 2012, with its 22-nanometer (nm) processor,
Intel was able to boast having the world's smallest and most advanced transistors
in a mass-produced product. In 2014, Intel launched an even smaller, more
powerful 14nm chip; and currently, the company is struggling to bring its 10nm
chip to market. For perspective, one nanometer is one-billionth of a meter,
smaller than the wavelength of visible light. The diameter of an atom ranges
from about 0.1 to 0.5 nanometers.
Hello, my name is Swarnali Ghosh. I'm committed to provide easy and in-depth tutorials on various technologies. No one is perfect in this world and nothing is eternally best. But we can try to be better. I hope it will help you a lot.
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