MOSFET-only switched-capacitor circuits in digital CMOS technologies

Design techniques are described for high-linearity switched-capacitor (SC) stages constructed entirely from MOS transistors. The proposed circuits use the gate-to-channel capacitance of MOSFETs for realizing all capacitors. As a result, they can be fabricated in any inexpensive basic digital CMOS technology, and the chip area occupied by the capacitors is much reduced. A number of different SC stages have been designed and fabricated using the proposed techniques. These included SC amplifiers, gain/loss stages and data converters. Both the simulations and the experimental results obtained indicated that very high linearity can be achieved in these circuits