高线性度CMOS射频AB类功率放大器设计

CMOS RF Class AB Amplifier Design with High Linearity

摘要: CMOS射频AB类功率放大器广泛应用于单片集成无线芯片内.采用恒定最大电流的方法对其效率进行分析，采用归一化输入电压的方法对其线性度进行分析.利用AB类功率放大器系统增益的非线性与CMOS跨导非线性相互补偿，提高了CMOS射频 AB类放大器的线性度.基于TSMC 0.18 μm CMOS 混合信号工艺，设计了一款两级射频AB类功率放大器.该射频功率放大器差动输入，单端输出，工作频段为804~940 MHz，工作电压为3 V.仿真指标为：增益为11 dB，输出1 dB压缩点为17.2 dBm，OIP3为18.2 dBm，附加效率为37%.

Abstract: CMOS radio frequency class AB power amplifiers are widely used in single chip wireless solutions. Efficiency is analyzed under constant maximum current and linearity analysis by using normalization method of input voltage. High linearity is achieved with the compensation between system gain and MOS transconductance, both are nonlinear. A two stage RF class AB power amplifier is designed based on TSMC 0.18 μm CMOS mixed-signal process. With a differential input and a signal-end output, this RF power amplifier works in the frequency band of 804~940 MHz under operating voltage of 3 V. Simulation shows:the gain is 11 dB, the P1 dB is 17.2 dBm, the OIP3 is 18.2 dBm and the PAE is 37%.