创新单级环形振荡器的研制

Research and Fabrication of a Novel Single Stage Ring Oscillator

提出了一款创新的单级环形振荡电路。该电路通过采用交叉耦合结构,制造额外的极点,使单级放大电路的相位交点总是发生在增益交点之前,此时根据巴克豪森准则,电路在环路相移为180°时增益仍然大于1,因此电路可持续振荡。此外,为了验证该振荡器的实用性,设计了一款以该振荡器作为VCO的可编程锁相环。电路采用标准0.5μm CMOS工艺制造,流片结果显示该电路最高能工作在1.005 GHz,此时相位噪声达到-81 dBc/Hz@1 MHz.

A new single stage ring oscillator was designed.Cross coupled circuit was employed to get more poles,which made the phase crossover before the gain crossover.Based on Barkhausen criterion,the gain was greater than one when the phase shift of the loop was 180°,then now this circuit could oscillate.A programmable PLL was designed to verify the performance of this oscillator.Standard 0.5 μm CMOS Process was used to design a PLL with this single stage ring oscillator.While operating at 1.005 GHz,the phase noise in the locked condition is -81 dBc/Hz@ 1MHz offset.