Abstract
This paper presents the design consideration of a four-stage variable gain amplifier (VGA) with a wide dynamic range for receivers. The VGA uses parallel amplifiers for the first and second amplifiers in order to improve the input third-order intercept point (IIP3) in the low gain region. To investigate the behavior of the VGA, the gain and linearity analyses are newly derived for the parallel amplifiers, and are compared with the measured results. In addition, the principle of the temperature compensation is described. The gain control range of 110dB, the IP1dB of -11dBm, and noise figure (NF) of 5.1dB were measured using a 0.5µm 26GHz fT BiCMOS process.
