09-09-2016, 09:29 AM
1453942358-LICeinsteinedition.pdf (Size: 3.58 MB / Downloads: 5)
Integrated Circuits:
An integrated circuit (IC) is a miniature, low cost electronic circuit consisting of active and
passive components fabricated together on a single crystal of silicon. The active components are
transistors and diodes and passive components are resistors and capacitors.
Advantages of integrated circuits:
Miniaturization and hence increased equipment density.
Cost reduction due to batch processing.
Increased system reliability due to the elimination of soldered joints.
Improved functional performance.
Matched devices.
Increased operating speeds.
Reduction in power consumption
Classification:
Integrated circuits can be classified into analog, digital and mixed signal (both analog and digital
on the same chip). Based upon above requirement two different IC technology namely Monolithic
Technology and Hybrid Technology have been developed. In monolithic IC ,all circuit
components ,both active and passive elements and their interconnections are manufactured into or
on top of a single chip of silicon. In hybrid circuits, separate component parts are attached to a
ceramic substrate and interconnected by means of either metallization pattern or wire bounds.
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.
Analog ICs, such as sensors, power management circuits, and operational amplifiers, work by
processing continuous signals. They perform functions like amplification, active filtering,
demodulation, mixing, etc. Analog ICs ease the burden on circuit designers by having expertly
designed analog circuits available instead of designing a difficult analog circuit from scratch.
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
Generations
SSI, MSI and LSI
The first integrated circuits contained only a few transistors. Called "Small-Scale Integration"
(SSI), digital circuits containing transistors numbering in the tens provided a few logic gates for
example, while early linear ICs such as the Plessey SL201 or the Philips TAA320 had as few as
two transistors. The term Large Scale Integration was first used by IBM scientist Rolf Landauer
when describing the theoretical concept, from there came the terms for SSI, MSI, VLSI, and ULSI.
They began to appear in consumer products at the turn of the decade, a typical application being
FM inter-carrier sound processing in television receivers.
The next step in the development of integrated circuits, taken in the late 1960s, introduced devices
which contained hundreds of transistors on each chip, called "Medium-Scale Integration" (MSI).
They were attractive economically because while they cost little more to produce than SSI devices,
they allowed more complex systems to be produced using smaller circuit boards, less assembly
work (because of fewer separate components), and a number of other advantages.
VLSI
The final step in the development process, starting in the 1980s and continuing through the present,
was "very large-scale integration" (VLSI). The development started with hundreds of thousands of
transistors in the early 1980s, and continues beyond several billion transistors as of 2007.
In 1986 the first one megabit RAM chips were introduced, which contained more than one million
transistors. Microprocessor chips passed the million transistor mark in 1989 and the billion
transistor mark in 2005
ULSI, WSI, SOC and 3D-IC
To reflect further growth of the complexity, the term ULSI that stands for "Ultra-Large Scale
Integration" was proposed for chips of complexity of more than 1 million transistors.
Wafer-scale integration (WSI) is a system of building very-large integrated circuits that uses an
entire silicon wafer to produce a single "super-chip". Through a combination of large size and
reduced packaging, WSI could lead to dramatically reduced costs for some systems, notably massively parallel supercomputers. The name is taken from the term Very-Large-Scale Integration,
the current state of the art when WSI was being developed.
System-on-a-Chip (SoC or SOC) is an integrated circuit in which all the components needed for a
computer or other system are included on a single chip. The design of such a device can be
complex and costly, and building disparate components on a single piece of silicon may
compromise the efficiency of some elements.
However, these drawbacks are offset by lower manufacturing and assembly costs and by a greatly
reduced power budget: because signals among the components are kept on-die, much less power is
require. Three Dimensional Integrated Circuit (3D-IC) has two or more layers of active electronic
components that are integrated both vertically and horizontally into a single circuit.
Communication between layers uses on-die signaling, so power consumption is much lower than
in equivalent separate circuits. Judicious use of short vertical wires can substantially reduce overall
wire length for faster operation.