DocumentCode :
1002663
Title :
An Over-60 dB True Rail-to-Rail Performance Using Correlated Level Shifting and an Opamp With Only 30 dB Loop Gain
Author :
Gregoire, B. Robert ; Moon, Un-Ku
Author_Institution :
Sch. of Electr. Eng. & Comput. Sci., Oregon State Univ., Corvallis, OR
Volume :
43
Issue :
12
fYear :
2008
Firstpage :
2620
Lastpage :
2630
Abstract :
Correlated level shifting (CLS) is introduced as a new switched-capacitor technique to provide true rail-to-rail performance while reducing errors from finite opamp gain. There is negligible kT/C noise increase and in many cases a speed advantage compared to using a high gain opamp. The gain enhancement is quantified with formulas and the general technique is compared to correlated double sampling (CDS). Results are presented from a 0.18 mum CMOS testchip of a 20 MHz, 12-bit pipelined A/D converter using CLS to reduce errors from finite opamp dc gain and limited opamp swing. It achieves 10.5 ENOB operating beyond the supply rails using an opamp circuit with 30 dB loop gain and 0.9 V supply.
Keywords :
CMOS integrated circuits; analogue-digital conversion; operational amplifiers; switched capacitor networks; CMOS; correlated level shifting; frequency 20 MHz; gain enhancement; opamp; pipelined A/D converter; size 0.18 mum; switched-capacitor technique; true rail-rail performance; voltage 0.9 V; Analog circuits; Analog-digital conversion; Circuit testing; Computer errors; Computer science; Moon; Performance gain; Rail to rail amplifiers; Sampling methods; Voltage; Correlated double sampling (CDS); correlated level shifting (CLS); pipelined analog-to-digital converter; rail-to-rail;
fLanguage :
English
Journal_Title :
Solid-State Circuits, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9200
Type :
jour
DOI :
10.1109/JSSC.2008.2006312
Filename :
4684624
Link To Document :
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