Design of continuous-time filters using transistor-only CMOS circuits

A design methodology for fully integrated, VLSI-compatible continuous-time filters is proposed. The design is based on a transistor-only integrator which utilizes the intrinsic capacitances of a transistor in saturation. Based on the integrator, possible structures of continuous-time filters are explored and the fabricated chips are tested. To facilitate the circuit analysis, a new method to generate and simplify a symbolic expression of an analog circuit network function is presented; this new method is on the average more efficient than previous such approaches and thus can be used to analyze larger circuits than in the past. Detailed error analysis is done to ensure reasonable symbolic function simplification. A computer program SAUCES is developed to simplify symbolic circuit functions and to analyze sensitivity of symbolic circuits