ON THE ELIMINATION OF REACTIVE ELEMENT LOOPS AND THE USE OF SPECIAL APPROXIMATIONS IN THE DESIGN OF OTA-C FILTERS

Loops of reactive elements in passive filters cause a series of proble ms in OTA-C simulations of these structures. These loops call be elimi nated in a systematic way by the procedures described in the paper. Th e use of special approximations in the design of the passive prototype filters allows the elimination of multiple loops of reactive elements that appear in usual LC ladder filters with finite transmission zeros . This leads to more efficient active simulations, where problems with floating capacitors, DC or high-frequency instability, or limited ope rating frequency are avoided.