Digital integrated circuits

Digital integrated circuits are capable of performing logic functions. Some examples of digital integrated circuits are logic gates, flip-flops, counters and shift registers. Monolithic technology is employed for the construction of these devices since this technology is inexpensive and yields superlative performance. The performance level of a digital integrated circuit can be assessed from its properties like noise immunity, noise generation, operating speed, operating temperature range, logic flexibility, cost, fan-in/fan-out, supply voltage, power dissipation and availability of complex functions. High noise immunity is preferred in logic gates to counter false logic signals. The different noises produced in a digital IC are external noise, power line noise, cross-talk noise, signal current noise, noise due to transmission line reflections and noise due to current spikes. For better results, operation speeds of digital ICs are kept high. Wide operating temperature range is preferred in digital ICs. Logic flexibility of a digital IC is a measure of its utility in meeting the various system needs. Standard supply voltage, low power dissipation and availability of complex functions are some other requirements of a digital IC. Different digital IC families are DTL, HTL, TTL, ECL, MOS and CMOS.