Low Power 8-b CMOS Current Steering Folding-Interpolating A/D Converter

Zhi-Yuan CUI
Nam-Soo KIM
Kie-Yong LEE
Ho-Yong CHOI

IEICE TRANSACTIONS on Electronics   Vol.E91-C    No.1    pp.81-86
Publication Date: 2008/01/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.1.81
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
A/D converter,  current steering folder,  interpolation,  CMOS process,  

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This paper presents a CMOS A/D converter based on the folding and interpolating technique. A current steering folder composed of differential pairs allows low power operation and an interpolation is used for high speed with low supply voltage. In a folding circuit, only twenty-three MOSFETs are required to have eight reference voltages of an 8-b A/D converter. The interpolation is implemented with a current division technique to generate 32 folding signals. This approach requires much less area and power consumption than other conventional flash A/D converter. The simulation in a 0.35 µm CMOS process achieves 8-b resolution at 250 Msample/s with power consumption 70 mW at 3.3 V power supply. The preliminary experiment indicates the current steering folder and coarse bits operate as expected.