Current-mode multiple-loop feedback filters using dual-output OTAs and grounded capacitors

A systematic method is presented for the generation, analysis and synthesis of current-mode continuous-time multiple-integrator-loop all-pole filters using dual-output operational transconductance amplifiers and grounded capacitors (DO-OTA-GC). The general theory based on a multiple-loop feedback model is formulated. A number of architectures including canonical realizations are developed, with particular emphasis on high-order configurations. A sensitivity analysis method is also given and parasitic effects on the structures are discussed. The general formulations are verified by direct analysis of the generated individual circuits. Design examples are also presented.