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michrochip fundamental


In electronics, an integrated circuit – also known as IC, microcircuit, microchip, silicon chip, or chip – is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a thin substrate of semiconductor material.

MIcrochips, the common term associated with Integrated circuits essentially breaks down to a combination of transistors which are simply electronic components which control electrical circuits in a simple series ofI’s and O’s or connections and disconnections, in order to operate and control many carefully calculated electrical functions that make amazing things possible.

Microchip is a generic term used for semiconductor integrated circuits (ICs). The function and features of a microchip will depend on what exactly the device is. Examples of microchips include micro processors, memory. digital signal processors etc used in various products..

An integrated circuit, commonly referred to as an IC, is a microscopic array of electronic circuits and components that has been diffused or implanted onto the surface of a single crystal, or chip, of semiconducting material such as silicon. It is called an integrated circuit because the components, circuits, and base material are all made together, or integrated, out of a single piece of silicon, as opposed to a discrete circuit in which the components are made separately from different materials and assembled later. ICs range in complexity from simple logic modules and amplifiers to complete microcomputers containing millions of elements.

The impact of integrated circuits on our lives has been enormous. ICs have become the principal components of almost all electronic devices. These miniature circuits have demonstrated low cost, high reliability, low power requirements, and high processing speeds compared to the vacuum tubes and transistors which preceded them. Integrated circuit microcomputers are now used as controllers in equipment such as machine tools, vehicle operating systems, and other applications where hydraulic, pneumatic, or mechanical controls were previously used. Because IC microcomputers are smaller and more versatile than previous control mechanisms, they allow the equipment to respond to a wider range of input and produce a wider range of output. They can also be reprogrammed without having to redesign the control circuitry. Integrated circuit microcomputers are so inexpensive they are even found in children’s electronic toys.

The first integrated circuits were created in the late 1950s in response to a demand from the military for miniaturized electronics to be used in missile control systems. At the time, transistors and printed circuit boards were the state-of-the-art electronic technology. Although transistors made many new electronic applications possible, engineers were still unable to make a small enough package for the large number of components and circuits required in complex devices like sophisticated control systems and handheld programmable calculators. Several companies were in competition to produce a breakthrough in miniaturized electronics, and their development efforts were so close that there is some question as to which company actually produced the first IC. In fact, when the integrated circuit was finally patented in 1959, the patent was awarded jointly to two individuals working separately at two different companies.

After the invention of the IC in 1959, the number of components and circuits that could be incorporated into a single chip doubled every year for several years. The first integrated circuits contained only up to a dozen components. The process that produced these early ICs was known as small scale integration, or SSI. By the mid-1960s, medium scale integration, MSI, produced ICs with hundreds of components. This was followed by large scale integration techniques, or LSI, which produced ICs with thousands of components and made the first microcomputers possible.

The first microcomputer chip, often called a microprocessor, was developed by Intel Corporation in 1969. It went into commercial production in 1971 as the Intel 4004. Intel introduced their 8088 chip in 1979, followed by the Intel 80286, 80386, and 80486. In the late 1980s and early 1990s, the designations 286, 386, and 486 were well known to computer users as reflecting increasing levels of computing power and speed. Intel’s Pentium chip is the latest in this series and reflects an even higher level.

A microprocessor — also known as a CPU or central processing unit — is a complete computation engine that is fabricated on a single chip. The first microprocessor was the Intel 4004, introduced in 1971. The 4004 was not very powerful — all it could do was add and subtract, and it could only do that 4 bits at a time. But it was amazing that everything was on one chip. Prior to the 4004, engineers built computers either from collections of chips or from discrete components (transistors wired one at a time). The 4004 powered one of the first portable electronic calculators.

If you have ever wondered what the microprocessor in your computer is doing, or if you have ever wondered about the differences between types of microprocessors, then read on. In this article, you will learn how fairly simple digital logic techniques allow a computer to do its job, whether its playing a game or spell checking a document!

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The current flow that charges the circuit node to a 0 is steered away from the circuit through a different kind of transistor (NMOS) connected between the circuit and the negative supply voltage, or electrical ground. Again, current will flow through the NMOS transistor for a very brief interval, but for the NMOS the current is between the circuit and the negative supply. In either case, the current flow results in a change in the circuit voltage, and the circuit voltage represents a bit of information. So, when a gate is controlling current flow, it is actually controlling the flow of information.

“Returning to the analogy between the farm and the computer chip, it is obvious that the flow is different (farm animals compared to information) and that the gate itself is different (a physical barrier compared to a transistor in the CMOS technology). But the most important difference is the means of controlling the flow. On the farm, the farmer resets the gate location by making a decision and then moving a physical barrier. A flow of animals through a complex maze of gates would require a farm hand at each gate.

“But in a computer chip, the control mechanism is the voltage on the control terminal of a transistor. This voltage turns on a transistor by changing its characteristics from that of an open circuit (the ‘off’ position) to one that can conduct a small current. This control voltage, in turn, is already available within the chip as a voltage at a point on another circuit. And, being a voltage on a circuit, this control mechanism represents a different bit of information.

“The overwhelming computing power of logic gates stems from the fact that the output of any particular gate is a voltage, which can in turn be used to control another gate. A computer chip therefore can be designed to make complex decisions about the information flow within itself. This ability enables sophisticated systems to be created by interconnecting as many as a million gates within a single chip. All of this with no farm hands and no moving parts.”

“Those of us who design logic gates for computers seldom reminisce on how the terms we use to describe technology came into use. The vision of a gate swinging back and forth clearly does not literally represent the structures on a silicon chip. But the reason for the usage of the term ‘gate’ for computer logic can be appreciated by examining the basic function of a gate: to control a flow.

“On a farm, gates may be used to control the ‘flow’ of sheep or goats between pens. In this case, the gate consists of a physical barrier whose position is controlled by a farmer. The farmer makes a decision about the flow of animals and then moves the physical barrier to permit the desired flow.

“In a computer, a gate controls the flow of electric current through a circuit. The gate consists of transistors; the transistors are selected by the chip designer from two basic types (PMOS and NMOS transistors) that are found in the ubiquitous CMOS (complementary metal-oxide semiconductor) technology. The current that flows through a gate establishes a voltage at a particular point in the circuit. This voltage represents a single ‘bit’ of information. The voltage may either be high (representing the value ‘1’) or low (representing the value ‘0’).

“To establish a 1 on a circuit, the current flow is steered to the circuit (controlled) by ‘turning on’ a PMOS transistor connected between the circuit and the positive supply voltage. The supply voltage is usually an industry-standard value such as 3.3 or 5.0 volts. For the very brief interval that is required for a logic gate to switch (on the order of a nanosecond, or a billionth of a second), current will flow through a PMOS transistor from the positive power supply to the circuit.

Microchip is a generic term used for semiconductor integrated circuits (ICs). The function and features of a microchip will depend on what exactly the device is. Examples of microchips include micro processors, memory. digital signal processors etc used in various products..





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