一种低闪烁噪声高线性度WLAN混频器的设计

Design of a WLAN Mixer with Low Flicker Noise and High Linearity

提出一种适用于零中频接收的WLAN混频器,采用折叠结构降低开关对的偏置电流,以得到良好的闪烁噪声性能;通过在混频器的驱动级引入辅助管,并优化其衬底电压和尺寸来抵消跨导管的非线性,进而提升电路的线性度。利用Volterra级数辅助分析制约线性度特性的限制因素。基于Chartered 0.18μm CMOS工艺的Spectre-RF仿真表明,电路在WLAN的2.4GHz频段具有良好的电学性能,噪声系数为8.6dB,闪烁噪声角为105kHz,IIP3为5.8dBm,芯片整体功耗为10mW,核心电路占用面积为0.09mm2。

A WLAN mixer was designed for zero IF receiver.Low flicker noise was achieved by using folded architecture to reduce bias current of switching pairs.Auxiliary transistor with optimized bulk voltage and size was adopted to cancel the nonlinearity of transconductance transistor,thus improving linearity of the mixer.Volterra series was used to analyze factors limiting linearity of the mixer.Spectre-RF simulations based on Chartered 0.18 μm CMOS process indicated that,at 2.4 GHz band of WLAN,the proposed mixer had a noise figure of 8.6 dB,a flicker noise corner of 105 kHz,and an IIP3 of 5.8 dBm.The chip consumed 10 mW of power,and the kernel circuit occupied a chip area of 0.09 mm2.