A Highly Linear CMOS IF Variable Gain Amplifier withExponential Gain Control
Ting-Hua Yun, Tang Shoulong, Longxing Shi · 2006
A highly linear intermediate frequency variable gain amplifier (VGA) with exponential gain control is developed using a transconductance linearization scheme.It consists of a variable-gain cell based on a current-steering structure,a novel wide-range exponential voltage generator,and a stage of a fixed-gain amplifier.The VGA is fabricated in 0.25μm CMOS technology. Measurements show that a continuous-gain control range of 8～48dB and a 3rd intermodulation distortion of better than -60dBc at a differential output of 1V peak-to-peak are obtained.The noise figure at maximum gain is 8.7dB,and the OIP3 loaded with 50Ω is 14.2dBm.