高动态范围CMOS接收信号强度指示器设计

摘要

采用0�18μm RF CMOS工艺设计了一种具有宽输入动态范围的接收信号强度指示器（ RSSI）。采用逐级检波式对数放大器结构，以分段线性近似法实现对数传输特性，使RSSI输出电压正比于输入功率的对数值。电路采用直流耦合方式以降低寄生参数并减少电路面积，并采用直流失调消除环路（ DCOC）解决直流耦合方式所带来的直流偏移电压影响，有效降低直流失调和低频噪声。仿真结果显示，该RSSI可检测输入信号动态范围大于60 dB，对数精度小于±1 dB。采用1�8 V电源电压供电，电路总电流消耗为11 mA，芯片核心面积为0�23 mm2。%A high dynamic range linear radio signal strength indicator is presented using a 0.18μm RF CMOS process.In order to achieve piecewise linear approximation of the logarithmic function,successive detection logarithmic amplifier architecture is adopted so that the output voltage is proportional to the logarithm value of the input power.DC coupling is used to achieve small parasitic parameter as well as low area.DC offset cancellation circuit is also introduced to cancel the DC offset due to the DC coupling.The simulation results show that the dynamic range of this RSSI is larger than 60 dB with the logarithm⁃error within ± 1 dB. The chip occupies an area of 0.23 mm2 ,and the total current consumption is 11 mA with a 1.8 V supply.