A Wide Gain Control Range V-Band CMOS Variable-Gain Amplifier With Built-In Linearizer

In this paper, the design and analysis of a CMOS variable gain amplifier (VGA) with the built-in linearizers and noise reduction technique are presented. A V-band low power and miniature VGA is designed and fabricated. To maximize the gain control range and to improve the linearity, an auxiliary nMOS transistor is added in the cascode structure as a built-in linearizer. Moreover, to reduce the noise figure (NF), an inductor is placed between the transistors in the cascode structure. At the high gain state, the VGA offers a maximum gain of 22 dB with a minimum NF of 4.8 dB at 62 GHz. Due to the built-in linearizers, the VGA demonstrates 40-dB gain control range with a third-order input intercept point (IIP₃) of -19 dBm at 60 GHz. At the low gain state, the VGA has 3 dBm of IIP₃. In both states, the power consumption is 26 mW from a 2-V voltage supply. The chip size is 0.91 × 0.69 mm², including pads. To the authors´ knowledge, this VGA demonstrates largest gain control range, the lowest power consumption, and the lowest NF at the high gain state for reported 90-nm CMOS millimeter-wave VGAs.