A CMOS dB-linear VGA with pre-distortion compensation for wireless communication applications

Abstract

This paper describes a CMOS dB-linear variable gain amplifier (VGA) that can provide a variable gain of 60dB while maintaining its 3dB bandwidth greater than 10 MHz. An exponential circuit is proposed to obtain the dB-linear control characteristics. The non-ideal effects on dB linearity are analyzed and the corresponding compensation methods are suggested. Simulation results based on a 0.35/spl mu/m CMOS technology are presented to demonstrate the performance of the proposed dB-linear VGA.