Classification of Integrated circuits

Integrated circuits can be classified into analog, digital and mixed signal (both analog and digital on the same chip).
Digital integrated circuits can have anything from a few thousand to millions of logic gates, flip-flops, multiplexers, and other circuits in a few square millimeters. The small size of these circuits allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration. These digital ICs, classically microprocessors, DSPs, and micro controllers work using binary mathematics to process "one" and "zero" signals.
Analog ICs, such as sensors, power management circuits, and operational amplifiers, work by giving out continuous signals. They carry out functions like amplification, active filtering, demodulation, mixing, etc. Analog ICs ease the burden on circuit designers by having expertly designed analog circuits available instead of designing a hard analog circuit from scratch.
ICs can also combine analog and digital circuits on a single chip to generate functions such as A/D converters and D/A converters. Such circuits offer smaller size and lower cost, but must carefully account for signal interference