CMOS工艺实现的高性能串联耦合正交振荡器

本文提出了一个高性能的正交振荡器。该振荡器采用具有顶层厚金属的SMIC CMOS 0.18um工艺实现。采用cascode串联耦合来产生正交信号。对NMOS差分对管引入源级退化电容来抑制其1/f噪声转化为振荡器的近端相位噪声。并最终采用专用的低噪声,高电源抑制能力的LDO来供电。正交振荡器测试显示4.78GHz信号输出时1MHz频偏处相位噪声－123.3dBc/Hz.频率范围为4.09GHz到4.87GHz,17.5%的调谐范围。调谐增益在44.5MHz/V至66.7MHz/V之间。核心芯片面积不包含pad和ESD保护电路的为0.41mm2。     

High performance QVCO design with series coupling in CMOS technology

A high performance quadrature voltage-controlled oscillator（QVCO） is presented.It has been fabricated in SMIC 0.18μm CMOS technology with top thick metal.The proposed QVCO employed cascade serial coupling for in phase and quadrature phase signal generation.Source degeneration capacitance is added to the NMOS differential pair to suppress their flicker noise from up-conversion to close in phase noise.A dedicated low noise and high power supply rejection low drop out regulator is used to supply this QVCO.The measured phase noise of the proposed QVCO achieves phase noise of-123.3 dBc/Hz at an offset frequency of 1 MHz from the carrier of 4.78 GHz,while the QVCO core circuit and LDO draw 6 mA from a 1.8 V supply.The QVCO can operate from 4.09 to 4.87 GHz（17.5%）.Measured tuning gain of the QVCO(K_vco) spans from 44.5 to 66.7 MHz/V.The chip area excluding the pads and ESD protection circuit is 0.41 mm².