A new current mode CMOS variable gain amplifier using a new pseudo-exponential function

Abstract

In this paper, a new pseudo-exponential function is described and a new CMOS exponential-control variable gain amplifier (VGA) based on the new function is introduced. No multiplier is needed in the proposed approach. The VGA operates in current mode and includes two different stages. The first stage is a simple current amplifier while the second stage is an attenuator. The overall behavior of the stages gives the new pseudo-exponential function. The VGA circuit has been designed and simulated for a 0.18 μ CMOS process. Post layout results show that the circuit has a bandwidth of 164 MHz and a gain range of 32.5 dB between − 21 and + 11.5 dB.