A CMOS VGA with DC offset cancellation for direct-conversion receivers
A CMOS dB-linear variable gain amplifier (VGA) with a novel I/Q tuning loop for dc-offset cancellation is presented. The CMOS dB-linear VGA provides a variable gain of 60 dB while maintaining its 3-dB bandwi...
Saved in:
Main Authors: | , , |
---|---|
Other Authors: | |
Format: | Article |
Language: | English |
Published: |
2010
|
Subjects: | |
Online Access: | https://hdl.handle.net/10356/92153 http://hdl.handle.net/10220/6276 |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Institution: | Nanyang Technological University |
Language: | English |
Summary: | A CMOS dB-linear variable gain amplifier (VGA)
with a novel I/Q tuning loop for dc-offset cancellation is presented.
The CMOS dB-linear VGA provides a variable gain of 60 dB while
maintaining its 3-dB bandwidth greater than 2.5 MHz. A novel
exponential circuit is proposed to obtain the dB-linear gain control
characteristics. Nonideal effects on dB linearity are analyzed and
the methods for improvement are suggested. A varying-bandwidth
LPF is employed to achieve fast settling. The chip is fabricated
in a 0.35-µm CMOS technology and the measurement results
demonstrate the good dB linearity of the proposed VGA and show
that the tuning loop can effectively remove dc offset and suppress
I/Q mismatch effects simultaneously. |
---|