can IC do ?
| Descr. of known IC's
fig.1 - Intrgrated
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.
It is formed as a single unit by
diffusing impurities into single-crystal silicon, which then serves
as a semiconductor material, or by etching the silicon by means of
electron beams. 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.
In large-scale integration (LSI), as many as 5000 circuit elements,
such as resistors and transistors, are combined in a square of
silicon measuring about 1.3 cm (.5 in) on a side. Hundreds of these
integrated circuits can be arrayed on a silicon wafer 8 to 15 cm (3
to 6 in) in diameter. Larger-scale integration can produce a
silicon chip with millions of circuit elements. Individual circuit
elements on a chip are interconnected by thin metal or
semiconductor films, which are insulated from the rest of the
circuit by thin dielectric layers. Chips are assembled into
packages containing external electrical leads to facilitate
insertion into printed circuit boards for interconnection with
other circuits or components.
What can a IC do ?
In consumer electronics, ICs have
made possible the development of many new products, including
personal calculators and computers, digital watches, and video
games. They have also been used to improve or lower the cost of
many existing products, such as appliances, televisions, radios,
and high-fidelity equipment.
Computer technology, in particular, has benefited greatly. The
logic and arithmetic functions of a small computer can now be
performed on a single VLSI chip called a microprocessor, and the
complete logic, arithmetic, and memory functions of a small
computer can be packaged on a single printed circuit board, or even
on a single chip.
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
- ULSI (ultra large-scale
integration): More than 1 million electronic components per
There are two major kinds of
- analog (or linear) which are used
as amplifiers, timers and oscillators
- digital (or logic) which are used
in microprocessors and memories
Some ICs are combinations of both
analog and digital.
Description of a few types of
CMOS, in computer science, acronym
for complementary metal-oxide semiconductor. A semiconductor device
that consists of two metal-oxide semiconductor field effect
transistors (MOSFETs), one N-type and one P-type, integrated on a
single silicon chip. Generally used for RAM and switching
applications, these devices have very high speed and extremely low
power consumption. They are, however, easily damaged by static
Digital Signal Processor (DSP), an
integrated circuit designed for high-speed data manipulations, used
in audio, communications, image manipulation, and other
data-acquisiton and data-control applications.
Dynamic RAM (DRAM) in computer
science, a form of semiconductor random access memory (RAM).
Dynamic RAMs store information in integrated circuits that contain
capacitors. Because capacitors lose their charge over time, dynamic
RAM boards must include logic to "refresh" (recharge) the RAM chips
continuously. While a dynamic RAM is being refreshed, it cannot be
read by the processor; if the processor must read the RAM while it
is being refreshed, one or more wait states occur. Because their
internal circuitry is simple, dynamic RAMs are more commonly used
than static RAMs, even though they are slower. A dynamic RAM can
hold approximately four times as much data as a static RAM chip of
the same complexity.
EPROM, in computer science, acronym
for erasable programmable read-only memory. Also called
reprogrammable read-only memory (RPROM). EPROMs are nonvolatile
memory chips that are programmed after they are manufactured.
EPROMs are a good way for hardware vendors to put variable or
constantly changing code into a prototype system when the cost of
producing many PROM chips would be prohibitive. EPROMs differ from
PROMs in that they can be erased, generally by removing a
protective cover from the top of the chip package and exposing the
semiconductor material to ultraviolet light, and can be
reprogrammed after having been erased. Although EPROMs are more
expensive than PROMs, they can be more cost-effective in the long
run if many changes are needed.
PROM, acronym for programmable
read-only memory. In computer science, a type of read-only memory
(ROM) that allows data to be written into the device with hardware
called a PROM programmer. After a PROM has been programmed, it is
dedicated to that data, and it cannot be reprogrammed. Because ROMs
are cost-effective only when produced in large volumes, PROMs are
used during the prototyping stage of the design. New PROMs can be
created and discarded as needed until the design is
Reduced Instruction Set Computer
(RISC), a type of microprocessor that focuses on rapid and
efficient processing of a relatively small set of instructions.
RISC design is based on the premise that most of the instructions a
computer decodes and executes are simple. As a result, RISC
architecture limits the number of instructions that are built into
the microprocessor but optimizes each so it can be carried out very
rapidly-usually within a single clock cycle. RISC chips thus
execute simple instructions faster than microprocessors designed to
handle a much wider array of instructions.
ROM, acronym for read-only memory.
In computer science, semiconductor-based memory that contains
instructions or data that can be read but not modified. To create a
ROM chip, the designer supplies a semiconductor manufacturer with
the instructions or data to be stored; the manufacturer then
produces one or more chips containing those instructions or data.
Because creating ROM chips involves a manufacturing process, it is
economically viable only if the ROM chips are produced in large
quantities; experimental designs or small volumes are best handled
using PROM or EPROM. In general usage, the term ROM often means any
read-only device, including PROM and EPROM.
Static RAM (SRAM), in computer science, a form of
semiconductormemory (RAM). Static RAM storage is based on the logic
circuit known as a flip-flop, which retains the information stored
in it as long as there is enough power to run the device. A static
RAM chip can store only about one-fourth as much data as a dynamic
RAM chip of the same complexity, but static RAM does not require
refreshing and is usually much faster than dynamic RAM. It is also
more expensive. Static RAMs are usually reserved for use in
Semiconductors | Transistor |
Hardware inside your computer | VLSI Chips