A CMOS Low-Power Variable-Gain LNA Based on Triple Cascoded Common-Source Amplifiers and Forward-Body-Bias Technology

This paper presents a 15.8-30 GHz CMOS variable-gain LNA based on triple cascoded common-source (CS) amplifiers and forward-body-bias technology. The forward body bias (FBB) is utilized to effectively reduce the threshold voltage of the MOS transistor, and the minimum supply voltage for a MOSFET operating in the saturation region can be relaxed accordingly. Based on above strategy, a triple cascaded CS topology with low power is proposed with a 1.2 V standard power supply in 65-nm CMOS. In addition, the gain of the proposed topology can be adjusted via the body biasing, resulting in a variable-gain LNA successfully. For demonstration, a prototype of 15.8-30GHz variable-gain LNA is designed and fabricated in 65-nm CMOS technology with 0.3 mm
²
chip size. The prototype achieves a minimum noise figure of 4.7 dB, a maximum gain of 11.4 dB with 16.4 dB gain tuning range, while consuming only 2.16 mW from a 1.2 V supply.