Transistors and other semiconductor devices have made it possible to reduce the size of electronic circuits because of their small size and low power consumption. It is now possible to extend the principles behind semiconductors to complete circuits as well as individual components. The goal of the integrated circuit is to develop a single device to perform a specific function, such as amplification or switching, thus eliminating the separation between components and circuits.
Several factors have made the integrated circuit popular:
● It is reliable with complex circuits.
● It meets the need for low power consumption.
● It offers small size and weight.
● It is economical to produce.
● It offers new and better solutions to system problems.
Introduction to Integrated circuits
The first integrated circuit was conceived by Geoffrey
W. A. Dummer, a radar scientist for the Royal Radar Establishment of the British Ministry of Defense. He published his idea in Washington, D.C., on May 7, 1952. But by 1956, he had still failed to build a successful circuit based on his model.
At Texas Instruments, Jack Kilby was assigned in the summer of 1958 to develop a smaller electrical circuit. His idea evolved to fabricating all the components and the chip out of the same block (monolith) of semiconductor material. In September 1958, he constructed the first integrated circuit, and it worked perfectly. Making all the parts out of the same block of material and adding the metal needed to connect them as a top layer resulted in not needing individual discrete components and wires. The circuits could be made smaller, and the manufacturing process could be automated. Jack Kilby is probably most famous for his invention of the integrated circuit, for which he received the Nobel Prize in Physics in the year 2000.
Robert Noyce of Fairchild Semiconductor independently developed his own idea for integrated circuit construction a half a year later than Jack Kilby. Noyce’s circuit solved Kilby’s problem of interconnecting all the components on the chip. He added the metal as a final layer and then removed some of it so that the wires needed to connect the components were formed. This made the integrated circuit suitable for mass production.
Today, an integrated circuit (Ic) is a complete electronic circuit in a package no larger than that of a conventional low-power transistor. The circuit consists of diodes, transistors, resistors, and capacitors. Integrated circuits are produced with the same technology and materials used in making transistors and other semiconductor devices.
The most obvious advantage of the integrated circuit is its small size. An integrated circuit is constructed of a chip of semiconductor material approximately one- eighth of an inch square. It is because of the integrated circuit’s small size that it finds extensive use in military and aerospace programs. The integrated circuit has also transformed the calculator from a desktop instrument to a handheld instrument. Computer systems, once the size of rooms, are now available in portable models because of integrated circuits.
This small, integrated circuit consumes less power and operates at higher speeds than a conventional transistor circuit. The electron travel time is reduced by direct connection of the internal components.
Integrated circuits are more reliable than directly connected transistor circuits. In the integrated circuit, internal components are connected permanently. All the components are formed at the same time, reducing the chance for error. After the integrated circuit is formed, it is pretested before final assembly.
Many integrated circuits are produced at the same time. This results in substantial cost savings. Manufacturers offer a complete and standard line of integrated circuits. Special-purpose integrated circuits can still be produced to specification, but this results in higher costs if quantities are small.
Integrated circuits reduce the number of parts needed to construct electronic equipment. This reduces inventory, resulting in less overhead for the manufacturer and further reducing the cost of electronic equipment.
Integrated circuits do have some disadvantages. They cannot handle large amounts of current or volt- age. High current generates excessive heat, damaging the device. High voltage breaks down the insulation between the various internal components. Most integrated circuits are low-power devices, consuming from 5 to 15 volts in the milliamp range. This results in power consumption of less than 1 watt.
Only four types of components are included in integrated circuits: diodes, transistors, resistors, and capacitors. Diodes and transistors are the easiest to construct. Resistors increase in size as they increase in resistance. Capacitors require more space than resistors and also increase in size as their capacity increases.
Integrated circuits cannot be repaired. This is because the internal components cannot be separated. Therefore, problems are identified by individual circuit instead of by individual component. The advantage of this disadvantage is that it greatly simplifies maintaining highly complex systems. It also reduces the amount of time required for maintenance personnel to service equipment.
When all factors are considered, the advantages outweigh the disadvantages. Integrated circuits reduce the size, weight, and cost of electronic equipment while increasing its reliability. As integrated circuits become more sophisticated, they become capable of performing a wider range of tasks.
Questions
1. Define integrated circuit.
2. What are the advantages of integrated circuits?
3. What are the disadvantages of integrated circuits?
4. What components can be included in inte- grated circuits?
5. What is the procedure for repairing a faulty integrated circuit?