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Design >> Mixed-Signal Design >> DAC capacitor mismatch and DEM in multibit
https://designers-guide.org/forum/YaBB.pl?num=1184216586

Message started by caosl_zju on Jul 11^th, 2007, 10:03pm

Title: DAC capacitor mismatch and DEM in multibit
Post by caosl_zju on Jul 11^th, 2007, 10:03pm

hi,all
In multi-bit ΣΔ modulator, how to model the DAC capacitor mismatch in SIMULINK, and investigate the validity of DEM. Someone explain this for me is very grateful!

Title: Re: DAC capacitor mismatch and DEM in multibit
Post by Berti on Jul 11^th, 2007, 11:31pm

There is a Toolbox available on the matlab exchange server, which
includes models for DAC capacitor mismatch etc.:

http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=7589&objectType=file

Studying those models should help you to understand how capacitor mismatch
can be modeled.

Title: Re: DAC capacitor mismatch and DEM in multibit
Post by caosl_zju on Jul 12^th, 2007, 3:23am

hi, Berti, thanks for reply. I have this toolbox and run it before, it contains the capacitor mismatch, but now i have to find a appropriate method to alleviate this effect such as DEM in my project. how to model the DEM?

Title: Re: DAC capacitor mismatch and DEM in multibit
Post by Berti on Jul 12^th, 2007, 11:52pm

Vector-based DEM like CLA, ILA, DWA etc. are easy to model.
You basically just need a vector where you store the indices of
the unit capacitors and rotate the position of the unit capacitors
according to the algorithm.

The book from Steyaert gives an overview over the most common DEM and explains how they work.
Yves Geerts Michiel Steyaert and Willy Sansen , Design of Multi-Bit Delta-Sigma A/D Converters, Kluwer Academics, 2002 .

Title: Re: DAC capacitor mismatch and DEM in multibit
Post by caosl_zju on Jul 13^th, 2007, 3:24am

so sad, i can't get this book! :'(