A novel capacitance assignment procedure for the design of sensitivity- and noise-optimized sc-filters

A novel procedure that determines the capacitor values for a given integrator-based SC network with given capacitor ratios is presented. The procedure optimally distributes a limited capacitance area among the individual circuit capacitors by minimizing the overall capacitor spread while simultaneously minimizing either sensitivity or noise. Noise in SC circuits is a function of ideal SC design parameters such as capacitor ratios and capacitance levels and of the technology-dependent parameters describing the switches and amplifiers. In our description of the noise performance, we have found a characteristic point which is only a function of SC design parameters and can thus serve as a measure for the noise performance. For its description a closed-form expression is used, which has the same form as the corresponding sensitivity measure. With these expressions an efficient capacitance assignment optimization procedure is derived, which is implemented in the computer-aided design and optimization program package SCSYN.