IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Piecewise linear-in-dB variable gain amplifier to enhance integral nonlinearity
YooSung KimJeong-Kwon NamDaejeong Kim
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2009 Volume 6 Issue 12 Pages 857-863


A new technique to improve the integral nonlinearity of the “linear-in-dB” variable gain amplifier (VGA) by adopting a piecewise linear transfer curve rather than a single curve is presented. The conventional single curve which is the first-order approximation of the exponential function yields bigger deviation errors as the gain control code advances. The integral nonlinearity (INL) of the proposed piecewise linear curve can be managed to be smaller because one of divisional curves moves to another before the deviation becomes prominent. A generic circuit schematic without chip size overhead is suggested with its future expansion in mind, and a design in a 0.35µm CMOS process under 3.3V supply is proposed and verified.

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© 2009 by The Institute of Electronics, Information and Communication Engineers
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