Tool to calculate the width and length of capacitor for switched-capacitor band pass filter

Abstract

The switched capacitor (SC) circuits find their applications in many fields. Due to their lower size at low frequencies, higher density can be achieved compared to active RC counterparts. Still there are nonlinerarities in SC circuits, many which are due to error in fabrication process. As will be explained later, the performance of SC circuits depends on capacitance ratios instead on absolute values; hence as designer, we are interested in matching the capacitance ratios rather than absolute values.

This tool which we designed takes care that the width and length of the capacitors it gives as output, has area ratios and perimeter ratios equal for all capacitor pairs, thus taking care of the proper matching of all capacitor.