Review on Variable and Programmable Gain Amplifiers and Applications

Variable and programmable gain amplifiers have been a recurrent subject of study over the last 50 years, and, are increasingly used in different applications today. This work presents an overview of these amplifiers as to serve as an up-to-date source of information for studies and designs. Different architectures and techniques are presented and classified for both radio and intermediate frequencies, since there are major differences in the requirements according to bandwidth. Typical applications where VGAs and PGAs are employed are also presented.