A 4.5 GHz to 5.8 GHz tunable δσdigital receiver with Q enhancement

A digital receiver tunable from 4.5 GHz to 5.8 GHz is reported for the first time. The circuit is based on a 40 GS/s continuous-time bandpass δσ ADC with Q-enhancement. In addition to the center frequency, the receiver bandwidth is independently tunable between 120 MHz and 500 MHz. An SNR of 37.9 dB is measured at 5 GHz over 500 MHz bandwidth. Center frequency scaling of bandpass digital receivers from 2 GHz to 5.8 GHz is shown without changing the digital section and clock frequency of the ADC. The circuit, which consumes 2.09W from 2.5V supply, can be used as a broadband RF sampler for 5.8 GHz WLAN, or as the digital IF of a 60 GHz radio.