For example, if power efficiency is a priority, op amps are available that trade off less important parameters. These devices provide exceptional performance in a key parameter.
With CMOS, designers now have access to a wider range of precision op amps that go beyond “general purpose”. No particular parameter has exceptional performance, but at the same time, every parameter generally performs well enough to get the job done. Often, op amps provide basic all-around performance. This revolution in op amp technology has another, wider impact on circuit design: it completely changes how engineers can select components.
In addition, the use of digital techniques and other innovations allow op amp manufacturers to create new architectures that can provide greater precision, better power efficiency, and higher bandwidth all in a smaller package. (License No.The result is that manufacturers can now make CMOS op amps that offer higher precision than bipolar op amps. Notwithstanding, instructors are permitted to photocopy isolated articles for noncommercial classroom use without fee. Print edition: ISSN 0913-5685 Online edition: ISSN 2432-6380Īll rights are reserved and no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Op-amp / offset / calibration / D/A converter / resistor string / / / With this technique, miniaturization of a whole op-amp system can be achieved, because the layout size of each circuit consisting of op-amps can be reduced when using this offset correction circuit. The fabrication with standard 0.35µm CMOS, followed by actual measurement, has confirmed that the offset can be confined to no more than 1.5mV using the new calibration circuit. This reduced the area by more than 50% and realized low power consumption while maintaining the same accuracy as a conventional type of DAC. For the D/A converter which occupies most of the area for the additional calibration circuit, the Folded-Alternated Resistor String DAC was developed.
A closed-loop feedback system was developed to realize high-speed and accurate offset calibration action. This paper describes the development of a circuit system that enables the offset calibration of an op-amp circuit after production. Hiroyuki Morimoto, Hiroaki Goto ( KIT), Hajime Fujiwara ( NJR), Kazuyuki Nakamura ( KIT) VLD2011-65 DC2011-41 Ken-system: CMOS Op-amp Offset Calibration Technique Using a Closed Loop Offset Amplifier and Compact Resistor String DAC IEICE Technical Committee Submission SystemĬMOS Op-amp Offset Calibration Technique Using a Closed Loop Offset Amplifier and Compact Resistor String DAC
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