Efficient SI wave elliptic filters based on direct and inverse Bruton transformations

The paper describes an efficient method for designing switched-current elliptic-wave filters. The method is based on applying direct or inverse Bruton circuit transformation to an LC reference prototype prior to obtaining the equivalent wave filter. The method provides significant reduction in the switched-current circuit complexity, particularly for high-order filters, when compared with preciously published results. This is achieved by applying a suitable Bruton transformation to an appropriate prototype which results in simplified and reduced number of wave adapters. Simulation results based on 1.2 mu m CMOS digital process for highpass and bandpass elliptic filters are also included.