A 1.9 GHz low-voltage silicon bipolar receiver front-end for wireless personal communications systems

A 1.9 GHz wireless receiver front-end (low-noise preamplifier and mixer) is described that incorporates monolithic microstrip transformers for significant improvements in performance compared to silicon broadband designs. Reactive feedback and coupling elements are used in place of resistors to lower the front-end noise figure through the reduction of resistor thermal noise, and this also allows both circuits to operate at supply voltages below 2 V. These circuits have been fabricated in a production 0.8 μm BiCMOS process that has a peak npn transistor transit frequency (f_T) of 11 GHz. At a supply voltage of 1.9 V, the measured mixer input third-order intercept point is +2.3 dBm with a 10.9 dB single-sideband noise figure. Power dissipated by the mixer is less than 5 mW. The low-noise amplifier input intercept is -3 dBm with a 2.8 dB noise figure and 9.5 dB gain. Power dissipation of the preamplifier is less than 4 mW, again from a 1.9 V supply