High frequency compensated current-mode ladder filters using multiple output OTAs

A methodology to implement compensated current-mode filters using multiple output OTAs and based on RLC ladder filter prototypes is presented. The resulting structures are very compact and share the low sensitivity characteristics of the passive RLC prototypes. They can be realized as CMOS circuits since they use only grounded capacitors and OTAs with one of the input terminals grounded. Compensation techniques to minimize degradation in the filter response due to excess phase of OTA parasitic poles are discussed. Simulations with CMOS OTAs and experimental results from discrete circuit implementations using bipolar OTAs are presented that verify the proposed approach.>