ANALOG INTEGRATED CIRCUITS - Branko Dokić, Tatjana Pešić-Brđanin

ANALOG INTEGRATED CIRCUITS - Branko Dokić, Tatjana Pešić-Brđanin

Preface

Based on the operating mode of transistor as a basic active element, monolithic integrated circuits are divided into digital, analog (linear) and mixedsignal circuits. In digital circuits transistors operate in switching mode, so they are in either ON or OFF mode. Those modes represent bits. For practical reasons, bits are marked as ”0” or ”1”. In the early years of digital electronics, a bit sequence mostly represented numerical information, usually in binary code. Binary vocabulary is considerably enriched by digitalization of analog signals like audio or video signals. To digitalize a signal means to obtain its samples in discrete time intervals which, if close enough, can be used as its perfect replica.
Digital integrated circuits process a digital signal, and analog process an analog signal. Analog signal is continuous over time and space. While digital signal modes are very stable and mostly independent of parameters of integrated circuit elements, analog signal is highly dependent of physical and electrical parameters of semiconductor devices. It is why the analog
design is much more complex than digital one and requires intuition, rigor and creativity. Furthermore, analog integrated circuits use larger area active devices than digital designs and are usually less dense in circuitry.

These are only a few reasons why the development and production of digital integrated circuits were much faster than analog. The explosive growth of digital electronics is based on computers and other digital systems widely used today in very different areas of technology such as: automation, radio and telecommunications, robotics, measuring techniques, entertainment
electronics, automobile industry etc. The development and application of digital integrated circuits have a huge influence not only on development of economy, science and technology but on human civilization in general. Today we often say how everything is digitalized, and we even speak of digital intelligence.