A CMOS digital step X-type attenuator with low process variations

抄録

In this paper, a digital step X-type attenuator with low process variations is demonstrated using 90nm CMOS technology. The X-type attenuator uses MOSFETs as voltage controlled resistors, which influenced by process parameters. And a compensation circuit associated with the threshold voltage is employed to mitigate the process influence. The attenuator have a maximum attenuation range of 32dB with 0.5dB steps. The rms amplitude error and rms phase error are 0.42dB and 3.1° over 23.5-30 GHz respectively, and the insertion losse is 9.77dB at 25GHz. The core chip size is 0.48 mm².