- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- A 75-dB digitally programmable CMOS variable gain amplifier
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
A 75-dB digitally programmable CMOS variable gain amplifier Rahmatian, Behnoosh
Abstract
A 75-dB DIGITALLY PROGRAMMABLE CMOS VARIABLE GAIN AMPLIFIER Variable-gain amplifiers (VGAs) are essential building blocks of many communication systems. In this thesis, a monolithic low-power digitally programmable VGA with 75dB of gain range is presented. The VGA is targeted for power line communication systems in particular for automotive application; however, it is a generic block that can be use in other applications. The core of the design is based on the low-distortion source-degenerated differential amplifier structure. A gm-boosting circuit is also used to provide higher gain and improve gain accuracy. In this work, to control the gain a new technique is used which is based on digitally controlling: 1) the source-degeneration resistance, and 2) an additional resistance between the differential output nodes of each gain stage. The changes in the source-degeneration resistance handle the coarse tuning, and the changes in the latter resistance are used for fine gain tuning. The overall VGA consists of three such gain stages. As a proof of concept, a single gain stage with a gain range of 24dB and programmable in 2dB gain steps has been fabricated in a 0.18μm CMOS technology. The chip is tested and measurement results are obtained. Based on these measurement results, the design of the gain stage is optimized and a three-stage 75dB VGA is designed. Each stage has a digitally tunable gain range of 25dB, and fine gain tuning of 2.5dB per step. The bandwidth of the VGA is higher than 140MHz, and the gain error is less than 0.3dB. The overall VGA draws 6.5mA from a 1.8V supply. The noise figure of the system at maximum gain is 12.5dB, and the IIP3 is 14.4dBm at minimum gain. These performance parameters are either better or compare favorably with the reported state-of-the-art VGAs.
Item Metadata
Title |
A 75-dB digitally programmable CMOS variable gain amplifier
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
2007
|
Description |
A 75-dB DIGITALLY PROGRAMMABLE CMOS VARIABLE GAIN AMPLIFIER
Variable-gain amplifiers (VGAs) are essential building blocks of many communication systems.
In this thesis, a monolithic low-power digitally programmable VGA with 75dB of gain range is
presented. The VGA is targeted for power line communication systems in particular for
automotive application; however, it is a generic block that can be use in other applications. The
core of the design is based on the low-distortion source-degenerated differential amplifier
structure. A gm-boosting circuit is also used to provide higher gain and improve gain accuracy.
In this work, to control the gain a new technique is used which is based on digitally controlling:
1) the source-degeneration resistance, and 2) an additional resistance between the differential
output nodes of each gain stage. The changes in the source-degeneration resistance handle the
coarse tuning, and the changes in the latter resistance are used for fine gain tuning.
The overall VGA consists of three such gain stages. As a proof of concept, a single gain stage
with a gain range of 24dB and programmable in 2dB gain steps has been fabricated in a 0.18μm
CMOS technology. The chip is tested and measurement results are obtained. Based on these
measurement results, the design of the gain stage is optimized and a three-stage 75dB VGA is
designed. Each stage has a digitally tunable gain range of 25dB, and fine gain tuning of 2.5dB
per step. The bandwidth of the VGA is higher than 140MHz, and the gain error is less than
0.3dB. The overall VGA draws 6.5mA from a 1.8V supply. The noise figure of the system at
maximum gain is 12.5dB, and the IIP3 is 14.4dBm at minimum gain. These performance
parameters are either better or compare favorably with the reported state-of-the-art VGAs.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2011-03-09
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0100942
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.