TABLE OF CONTENTS In recent years, digital signal processing has progressively supplanted analog signal processing in chip design. This is due to it having lower development costs, better precision performance and dynamic range, as well as being easier to test. The role of analog circuits has been mostly restricted to electronic applications of interfacing digital systems to the external world. Nevertheless, when precise computation of numbers is not required (as is the case in systems designed for perception of a continuously changing environment), and massively parallel collective processing of signals is needed, low precision analog VLSI (very large scale integration) has proven to be more convenient than digital in terms of cost, size and/or power consumption [1].
In recent years mixed signal application-specific integrated circuits (ASICs) have become increasingly popular. The cooperative coexistence of analog and digital circuits is very beneficial since they compensate for each other's weaknesses. Hence, although in many aspects digital electronics is superior, in reality it requires a symbiotic relationship with analog.
Since the invention of the transistor more than 50 years ago, the progress of microelectronics can be summarised as follows: 15 per cent decrease in feature size per year, 30 per cent cost decrease per year, 50 per cent performance improvement and 15 per cent semiconductor market growth rate. The numbers speak for themselves. This exponential evolution made many experts in the 1990s assert that fundamental limits were about to be reached. Fortunately,...
