On the realization of DO-OTA-C oscillators

The basic aim of this paper is to give design considerations of current-mode high frequency DO-OTA-C oscillator topologies achieving noninteractive control of b and Omega(o) with a minimum number of components. Starting from DO-OTA-C (grounded capacitor) filter topologies, reported in the literature and employing a minimum number of components, novel DO-OTA-C oscillator topologies are generated by converting filters into oscillators. Furthermore, the influence of the OTA nonidealities on oscillator performance is investigated. The performance of the proposed topologies are demonstrated with SPICE simulation program. The oscillator configurations provide frequency control by changing the OTA transconductances with biasing currents without affecting oscillation condition and are very suitable for VLSI design since they are composed only of DO-OTAs and grounded capacitors. (C) 1998 Elsevier Science Ltd. All rights reserved.