一款高线性度正电压控制的压控衰减器

A high linearity voltage control attenuator with positive voltage control

针对高线性度压控衰减器对正电压作为控制信号的需求,基于GaAs赝配高电子迁移率晶体管(PHEMT)0.25μm工艺,设计了一款1~6 GHz正电压控制的高线性度微波单片压控衰减器(VCA)。该压控衰减器控制管芯选择电阻变化率更小的D-mode PHEMT晶体管,通过电压浮地技术和采用片上集成隔直电容的方式,对传统的T型衰减电路的拓扑结构进行改进,从而实现0~5 V的正电压控制和高线性度。芯片在片测试结果表明,基态插入损耗小于2.3 dB,端口输入、输出电压驻波比小于1.6∶1,压控衰减器的衰减动态范围为0~28 dB,芯片尺寸为1.75 mm×1.35 mm×0.1 mm。

Demand for a high linearity voltage variable attenuator with positive voltage as control signal,a 1~6 GHz MMIC Voltage Control Attenuator(VCA) using 0.25 μm GaAs PHEMT process technology was designed. The voltage controlled attenuator selects the D-mode PHEMT transistor with smaller resistance change rate. Through the voltage floating technology and the way of on-chip integrated DC isolation capacitor,the topology of the traditional T-type attenuator circuit is improved,so as to realize 0~5 V positive voltage controlled and high linearity. On-wafer measure results of the chip shows that the insertion loss is less 2.3 dB,the input and output voltage standing wave ratio is less 1.6∶1,the attenuation dynamic range of the voltage controlled attenuator is 0~28 dB. The chip size is 1.75 mm×1.35 mm×0.1 mm.