A Current-Mode, 30 dB Range with 0.5 dB Step, 0.1 to 6 GHz Attenuator for Wideband Receiver

In this paper, a wide band, current-mode attenuator designed for the attenuator-first wideband receiver in 28nm CMOS technology is presented. The proposed attenuator combines both advantages of the R-2R network and the binary resistor array, achieving a 30 dB attenuation range with 0.5 dB per step from 100 MHz to 6 GHz. The step error is within ±0.1 dB thanks to the proposed structure. Compared with the previous design, the proposed attenuator’s frequency response is not sensitive to the parasitic routing resistance at the virtual ground point. This enables the attenuator to achieve accurate attenuation even at 6 GHz. The S 11 parameter is below −10 dB over the whole operating frequency.