基于SiGe BiCMOS的全集成射频功率放大器设计

Design of Fully Integrated RF Power Amplifier Based on SiGe BiCMOS

提出了一种基于SiGe BiCMOS工艺的适用于移动设备的紧凑全集成功率放大器.设计采用cascode驱动级与共发射极功率级级联以提高放大器的功率增益,片上集成CMOS电源以提供偏置电流,采用分布式的镇流电阻和具有热负反馈效果的偏置电路补偿结温以防止放大器在高温工作时失效,并且采用一种紧凑的电路级的热耦合模型对所提出的热稳定措施进行仿真验证.后仿结果表明:PA在3.3 V供电下、2.4~2.5 GHz的工作范围内输出增益为32.5 dB,S11&S22<-10 dB,1 dB压缩点处的输出功率为25.4 dBm,在25℃的环境温度下最高结温小于65℃(饱和).芯片面积仅为1.25×0.76 mm^(2).测试结果表明:在-45~85℃的工作环境下,可以在增益要求为26.5~32.9 dB的应用中正常工作.1 dB压缩点处的输出功率为24.3 dBm.采用20 MHz 64-QAM OFDM信号测试,DEVM达到-30 dB的输出功率为18.1 dBm.

A compact fully integrated power amplifier for mobile devices based on the SiGe BiCMOS process is proposed.The design uses a cascode driver stage cascaded with a common emitter power stage to increase the power gain of the amplifier,integrates a CMOS power supply on-chip to provide bias current,and uses distributed ballast resistors and a bias circuit with thermal negative feedback effect to compensate the junction temperature so as to prevent amplifier failure at high-temperature operation.A compact circuit-level thermal coupling model is used to simulate and verify the proposed thermal stabilization measures.The post-simulation results show that PA has an output gain of 32.5 dB in the working range of 2.4~2.5 GHz under a 3.3 V power supply,S11&S22<-10 dB,and the output power at the 1 dB compression point is 25.4 dBm.The maximum junction temperature is less than 65℃(saturation).The chip area is only 1.25×0.76 mm2.The test results show that in the working environment of-45~85℃,the amplifier can work well in the application where the gain requirement is 26.5~32.9 dB.The output power at the 1 dB compression point is 24.3 dBm.Using a 20 MHz 64-QAM OFDM modulation signal test,the output power of DEVM reaching-30 dB is 18.1 dBm.