AROMA: An Area Optimized CAD Program for Cascade SC Filter Design

An area optimized computer-aided cascade switched-capacitor (SC) filter design program called AROMA is presented. The program contains several user-selectable filter approximation techniques. AROMA permits the user to make tradeoffs between several design parameters such as passive sensitivity, op-amp output voltage swings, clock frequency, and the total capacitance of the filter. The program has default values of the tradeoffs, however, each block in the cascade filter can be modified by the user to meet specific requirements. AROMA incorporates recent results of practical interest to the SC filter designer. The flexible structure of the program allows for easy addition of new results, i.e., refined efficient building blocks, additional filter approximations, etc. It can be used by the novice as well as by experienced designers. Furthermore, the program is user-oriented. It can start, in its simplest mode, with a set of frequency specifications. The output gives a circuit description file that can be layed out by an analog circuit layout generator program. Examples illustrating the practicalness of AROMA are given.