带自适应体偏置的宽带LC VCO自动幅度控制策略

摘要

为了优化宽带LC型压控振荡器(LC VCOs)相位噪声性能,提出一种自动幅度控制策略.该策略结合了自适应体偏置和数字校准.当VCO开始工作时,自适应体偏置技术使VCO在不同的工艺角、电压和温度(PVT)情况下快速起振.当谐振频率变化时,在自适应体偏置和数字校准的作用下,VCO的谐振幅度被控制在最优值附近,达到优化相位噪声的目的.在TSMC 0.18 μm CMOS工艺中,覆盖频率范围为1.6～3.2 GHz的宽带LC VCO用来验证该幅度控制策略的可行性.基于SpectreRF的仿真结果表明LC VCO的幅度变化率降低90％,且在3.2 GHz谐振频率,10 kHz频率偏移处的相位噪声改善8.2 dB.%In order to optimize the phase noise of the wideband LC voltage controlled oscillators (LC VCOS), a strategy of automatic amplitude control is proposed. The strategy combines adaptive body-bias technique with digital calibration. When VCO works, the adaptive body-biased technique ensures the VCO oscillating as soon as possible regardless of PVT variations. When oscillation frequency is changed, by using of the adaptive body-biased technique and the digital calibration, amplitude of wideband VCO could be adjusted to the level of optimal value for phase noise optimization. A wideband LC VCO with oscillation frequency ranging from 1. 6 GHz to 3. 2 GHz is used to verify the feasibility of the proposed strategy, which is implemented in TSMC 0. 18 祄 CMOS technology. SpectreRF based simulation results show amplitude derivation is reduced by ! Besides, phase noise at 3. 2 GHz carrier and 10 kHz frequency offset is 8. 2 dB better.