Abstract: A current-steering IF VGA based on an analog multiplier is designed.A nonlinear model is established and analyzed based on the MOSFET I-V model in strong inversion, and a linearity optimization method is presented.Simulation results based on 0.25 μm CMOS technology indicate that about a 33 dB decrease in the third order inter-modulation at maximum input and a 12 dB increase in gain control range of the optimized VGA with 3.3 V supply voltage are obtained.The ⅡP3 at the minimum gain setting is 17.5 dBm, and the minimum NF is 7.8 dB.

Key words: analog multiplier, variable gain amplifier, nonlinear distortion