In several consumer items, e.g., mobile phones and handheld computers, both digital and analog circuits are needed. Currently, it is easy to implement a big subsystem or even a complete system, that earlier demanded many chips, on a single chip. A system on chip (SoC) has usually the features of lower power usage and a little fabrication expense in contrast to multi-chip solutions.
Many analog systems need a stable power supply voltage that does not vary with temperature and time in order to operate properly. In a battery operated system the battery voltage is not stable, e.g. it decreases with decreasing temperature and with ageing.
Accurate, low-cost, rapid-prototyping techniques for analog circuits have been a long awaited dream for analog designers. However, due to the inherent nature of analog system, design automation in analog domain is very difficult to realize, and field programmable analog arrays (FPAA) have