Design and Implementation of class AB VGA in deep sub micron technology

Abstract

A variable gain amplifier (VGA) is an indispensible building block in many communication
systems. In communication receiver, VGA is typically employed in a feedback loop to realize an
automatic gain control (AGC). In this paper class AB VGA consisting of a linear transconductor amplifier
and a linear transimpedance amplifier, is designed, analyzed and simulated in GENERIC 0.13um CMOS
process(pre-layout and post-layout simulation is done) using Mentor Graphics Tool. The simulation
results shows that, the modified VGA has bandwidth of 1660MHz and gain of 66.01 dB and power
dissipation is less than 100uW at 1.2v supply voltage. The results show that the circuit is capable of
working with high linearity and wide bandwidth by varying Rf and Rs. The modified class AB VGA is
appropriate for low power, UWB applications.