A dB-Linear Variable Gain Amplifier for Zero-IF Receivers

This paper proposes a variable gain amplifier (VGA) with a common mode feedback (CMFB) loop and DC offset cancellation (DCOC) for better application in the zero-IF receivers. The VGA chip is fabricated in a 22nm CMOS technology and consuming power of 2.8mW under the supply voltage of 1V. The VGA realizes the dB-linear gain dynamic range of 40dB and its curve between the gain and control voltage achieves the exponential relationship by cascading. The chip area of this VGA is $145 \times 100 \mu \mathrm{m}^{2}$. The 3dB bandwidth is up to 300MHz, significantly satisfying the operating frequency band of 50MHz. The OP1dB of this VGA is over 2dBm, ensuring the good linearity of the entire receiver.