De Lima, Jader A. [UNESP]Agostinho, Peterson R. [UNESP]2014-05-272014-05-272004-09-07Proceedings - IEEE International Symposium on Circuits and Systems, v. 1.0271-4310http://hdl.handle.net/11449/67875A quasi-sinusoidal linearly tunable OTA-C VCO built with triode-region transconductors is presented. Oscillation upon power-on is ensured by RHP poles associated with gate-drain capacitances of OTA input devices. Since the OTA nonlinearity stabilizes the amplitude, the oscillation frequency f0 is first-order independent of VDD, making the VCO adequate to mixed-mode designs. A range of simulations attests the theoretical analysis. As part of a DPLL, the VCO was prototyped on a 0.8μm CMOS process, occupying an area of 0.15mm2. Nominal f0 is 1MHz, with K VCo=8.4KHz/mV. Measured sensitivity to VDD is below 2.17, while phase noise is -86dBc at 100-KHz offset. The feasibility of the VCO for higher frequencies is verified by a redesign based on a 0.35μm CMOS process and VDD=3.3V, with a linear frequency-span of l3.2MHz - 61.5MHz.engCapacitanceCMOS integrated circuitsComputer simulationElectric conductanceElectric potentialJitterLogic designMOSFET devicesSwitchingTransconductanceTransfer functionsOTAPhase noiseRing oscillatorsWaveformsVariable frequency oscillatorsTrabalho apresentado em evento10.1109/ISCAS.2004.1328313WOS:000223122300198Acesso aberto2-s2.0-4344578485