The small size of the IC is its most apparent advantage. A typical IC can be constructed on a piece of semiconductor material that is less than 4mm2. Even when the IC is suitably packaged, it still occupies only a small amount of space. The small size of the IC also produces other benefits such as they consume less power than the equivalent conventional circuit. They generate less heat and therefore generally do not require elaborate cooling or ventilation systems.
IC's are also more reliable than conventional circuits. This greater reliability result because every component within the IC is a solid-state device and is permanently connected together with a thin layer of metal. They are not soldered together like the components in a conventional circuit and a circuit failure due to faulty connections is less likely to occur.
It might appear that the IC has only advantages to offer and no real disadvantages. Unfortunately, this is not the case, since IC's are an extremely small device it cannot handle large currents or voltages. High currents generate heat within the device and small components can be easily damaged if the heat becomes excessive.
High voltages can break down the insulation between the components in the IC because the components are very close together. This can result in shorts between the adjacent components, which would make the IC completely useless. Therefore, most IC's are low power devices, which have a low operating current (milliamps) and low voltages (5 - 20V). Also, most IC's have a power dissipation range of less than 1 watt.
At the present only four types of component are commonly constructed within an IC. This makes only a narrow selection of components available, these are:
Diodes and transistors are the easiest components to construct and are used extensively to perform as many functions as possible within each IC. Resistors and capacitors may also be formed, but it is much more difficult and expensive to construct these components. The amount of space occupied by a resistor increases with its value and in order to conserve space, it is necessary to use resistors with values as low as possible.
Capacitors occupy even more space than resistors and the amount of space required increases with the value of the capacitor.
Ic's cannot be repaired because their internal components cannot be seperated. When one internal component becomes defective, the whole IC becomes defective and musty be replaced. This means that good components are often thrown away with the defective ones. This disadvantage is not as bad as it sounds, as the task of fault finding is simplified because it is only necessary to trace the problem to a specific circuit instead of an individual component. This greatly simplifies the task of maintaining highly complex systems and reduces the demands on maintenance personnel.