MOSFET-only switched-capacitor circuits in digital CMOS technology

Design techniques are described for the realization of precision high-linea rity switched-capacitor (SC) stages constructed entirely from MOS transisto rs. The proposed circuits use the gate-to-channel capacitance of MOSFET's f or realizing all capacitors. As a result, they can he fabricated in any ine xpensive basic digital CMOS technology, and the chip area occupied by the c apacitors can be reduced. A number of different SC stages have been designed and fabricated using the proposed techniques. These included SC amplifiers, gain/loss stages, and d ata converters. Both the simulations and the experimental results obtained indicate that very high linearity (comparable to that achieved using analog fabrication processes with two poly-Si layers) can be achieved in these ci rcuits using basic CMOS technology.