Integrated Circuits-Merits and Demerits
Merits or Advantages of Integrated Circuits
The integrated circuits offer a number of advantages over those made by interconnecting discrete components. These are summarized as follows:
1. Extremely small size—thousands times smaller than discrete circuit. It is because of fabrication of various circuit elements in a single chip of semi-conductor material.
2. Very small weight owing to miniaturized circuit.
3. Very low cost because of simultaneous production of hundreds of similar circuits on a small semiconductor wafer. Owing to mass production an IC costs as much as an individual transistor.
4. More reliable because of elimination of soldered joints and need for fewer inter-connections.
5. Low power consumption because of their smaller size.
6. Easy replacement as it is more economical to replace them than to repair them.
7. Increased operating speeds because of absence of parasitic capacitance effect.
8. Close matching of components and temperature coefficients because of bulk produc¬tion in batches.
9. Improved functional performance as more complex circuits can be fabricated for achieving better characteristics.
10. Greater ability of operating at extreme temperatures.
11. Suitable for small signal operation because of no chance of stray electrical pickup as various components of an IC are located very close to each other on a silicon wafer.
12. No component project above the chip surface in an IC as all the components are formed within the chip.
Demerits or Disadvantages of Integrated Circuits
The integrated circuits have few limitations also, as listed below :
1. In an IC the various components are part of a small semi-conductor chip and the individual component or components cannot be removed or replaced, therefore, if any component in an IC fails, the whole IC has to be replaced by the new one.
2. Limited power rating as it is not possible to manufacture high power (say greater than 10 Watt) ICs.
3. Need of connecting inductors and transformers exterior to the semi-conductor chip as it is not possible to fabricate inductors and transformers on the semi-conductor chip surface.
4. Operations at low voltage as ICs function at fairly low voltage.
5. Quite delicate in handling as these cannot withstand rough handling or excessive heat.
6. Need of connecting capacitor exterior to the semi-conductor chip as it is neither convenient nor economical to fabricate capacitances exceeding 30 pF. Therefore, for higher values of capacitance, discrete components exterior to IC chip are con¬nected.
7. High grade P-N-P assembly is not possible.
8. Low temperature coefficient is difficult to be achieved.
9. Difficult to fabricate an IC with low noise.
10. Large value of saturation resistance of transistors.
11. Voltage dependence of resistors and capacitors.
12. The diffusion processes and other related procedures used in the fabrication proc¬ess are not good enough to permit a precise control of the parameter values for the circuit elements. However, control of the ratios is at a sufficiently acceptable level.