Area-Efficient Switched Capacitor Non-Filtering Circuits: Sum- Gain Amplifiers

Abstract

Switched-capacitor rum-gain amplifier (SGAs) are widely used in parallel filter systems. The capacitance spread of such circuits is proportional to the coefficient spread, thus making conventional SGAs unsuitable for high gain applications. SGAs with different input phases and a SGA with the same input phase are discussed, and a new area-efficient SGA, which can reduce the capacitance spread to the square root of coefficient spread ration, is proposed. Furthermore, the non-ideal effects of op- amp like finite DC gain and offset voltage are compensated by using the offset storing capacitor. All the circuits designed here only use the bi-phase clocking scheme.