Cancel multiplexed DAC's output error, and add a sign bit

The circuit of Figure 2 employs an original, low-cost technique to take advantage of the HC`174052's low price. The multiplexer's internal resistance is inserted in the feedback loop of an op amp, and the error, E, is almost cancelled. To add a sign bit, the versatile circuit employs anoth...

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Bibliographic Details
Published in:Electronic design 2002-06, Vol.50 (12), p.98-98
Main Authors: Barbancho, Antonio, Biscarri, Felix
Format: Magazinearticle
Language:English
Subjects:
Design and construction
Multiplexers
Technology application
Online Access:Get full text
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Summary:The circuit of Figure 2 employs an original, low-cost technique to take advantage of the HC`174052's low price. The multiplexer's internal resistance is inserted in the feedback loop of an op amp, and the error, E, is almost cancelled. To add a sign bit, the versatile circuit employs another multiplexer and a unity-gain differential amplifier, which is fed with the DAC's output, or its inverse. This arrangement can be easily modified to add an arbitrary number of outputs by simply changing U3.
ISSN:0013-4872
1944-9550