Some techniques for low-voltage continuous-time analog circuit operation

The drastic reduction in the supply voltages of CMOS VLSI systems driven by technological as well as power reduction constraints has forced analog designers to divert from conventional analog circuit architectures. These become nonfunctional in a reduced supply environment. New techniques for low voltage, high performance operation of analog CMOS circuits are required for the new generations of deep submicrometer fine line CMOS technologies. In this presentation a family of high performance low-voltage analog CMOS circuits is introduced. These circuits are based on the utilization of static, dynamic and switched floating voltage sources, on floating and quasi-floating gate transistors and on a new versatile cell denoted flipped voltage follower. These circuits operate in all cases with a single supply voltage close to a transistor´s threshold voltage. Among the circuits discussed in this presentation we include: class AB op-amps, rectifiers, filters, linear transconductors, analog multipliers, oscillators, D-to-A and A-to-D converters, etc.