A monolithic SiGe HBT low noise amplifier using a novel resistive feedback configuration

A novel SiGe HBT low noise amplifier (LNA) was designed by adopting the feedback resistors, which are low cost and implemented easily in VLSI technology. Due to the absence of on-chip spiral inductor, the die area of this novel LNA decreases noticeably. The novel resistive feedback structure of the LNA comprising a shunt feedback loop and a series feedback loop, wherein the shunt feedback loop is used for the adjusting the noise performance, while the series feedback loop is used for adjusting the gain performance. Hence, by using the novel feedback technique, the traditional conflict between the gain and the noise performance could be resolved successfully for the amplifier. Finally, this monolithic SiGe HBT LNA with the novel feedback configuration was fabricated in 0.35-μm Si BiCMOS technique, and the die area of the LNA is only 0.282mm2. The measurement results show that in the band from 0.2 to 1.2GHz, the minimum noise figure(NF) is 2.5dB, the maximum gain is as high as 27dB, and both the input and output reflections(S11, S22) are less than -9dB. These results provide a significant guide for the design and development of integrated circuit based on Si technology.