← 返回 JSSC 论文列表JSSC 2006第7期RF & Wireless0.5μm SiGe BiCMOS
A Direct Conversion Receiver With an IP2 Calibrator for CDMA/PCS/GPS/AMPS Applications
采用共模反馈电路的IP2校准技术提升直接转换接收机性能
IIP2:64dBm, IIP3:4dBm, 噪声系数:6.5dB, 电压增益:42.2dB
直接转换接收机IP2校准共模反馈CDMASiGe BiCMOS
▸创新点1：采用共模反馈（CMFB）电路实现IP2校准，通过动态调整共模输出阻抗显著提升二阶输入截点（IIP2）性能，从44 dBm提升至64 dBm，改善幅度达20 dB。该方法解决了直接转换接收器中IP2失配的关键问题。
▸创新点2：设计可调共模输出阻抗的IP2校准器，通过独立控制正负混频器输出的CMFB增益，实现精准的共模阻抗匹配，降低二阶非线性失真，为CDMA/PCS/GPS/AMPS等多模应用提供适应性优化。
▸创新点3：在0.5μm SiGe BiCMOS工艺中集成IP2校准功能，单电源供电（2.7-3.1V）下实现42.2 dB电压增益、6.5 dB噪声系数和4 dBm IIP3，展示了高线性度与低噪声的协同设计能力。
▸创新点4：系统级创新通过CMFB与混频器的协同设计，将IP2校准从传统静态方法转为动态反馈控制，避免额外功耗开销，为直接转换架构的可靠性提供新解决方案。
Abstract
A second-order intercept point (IP2) calibra- tion technique is developed using common-mode feedback (CMFB) circuitry in a direct-conversion receiver for wireless CDMA/PCS/GPS/AMPS applications. The IP2 calibrator is ca- pable of providing different CMFB gain to tune its common-mode output impedance for each of the positive and negative mixer outputs. The CDMA mixer applying this method achieved a second-order input intercept point (IIP2) of 64 dBm, a third-order input intercept point (IIP3) of 4 dBm, a noise figure of 6.5 dB and a voltage gain of 42.2 dB. This result shows a 20 dB improvement from an uncalibrated IIP2 of 44 dBm. The receiver RFIC is implemented in a 0.5- m SiGe BiCMOS process, and it operates from a 2.7 to 3.1 V single power supply.