A DC-4GHz 6-Bit Digital Attenuator with High Accuracy and Low Insertion Loss

摘要

A DC to 4 GHz 6-bit digital attenuator with high accuracy and low insertion loss by enhancement/depletion (E/D) mode GaAs pseudomorphic high electron-mobility transistor (pHEMT) process is presented in this paper. The digital attenuator achieves a 31.5dB dynamic attenuation range stepped by 0.5dB with smaller than 2dB insertion loss and less than 0.36dB RMS attenuation error. The input and output return loss is less than -10dB for all attenuation states from DC to 4 GHz. Meanwhile the digital attenuator has built-in logic driving circuit which simplifies the control logic into a 6-bit positive voltage control. The total chip size is 2.7mm×1.95mm × 0.1 mm.