Biquadratic Filter Applications Using a Fully-Differential Active-Only Integrator

A new class of active filters, real active-only filters is described and possible implementation issues of these filters are discussed. To remedy these issues, a fully-differential active-only integrator block built around current controlled current conveyors is presented. The integration frequency of the proposed circuit is adjustable over a wide frequency range. As an application, a real active-only filter based on the classical two-integrator loop topology is presented and designed. The feasibility of this filter in a 0.35μm CMOS process is verified through SPECTRE simulation program in the CADENCE design tool.