As mentioned in for example Converter Passion and in other sources, even like this blog mentioning the top-ten resources, the ADI (Analog Devices, Inc.) home page contains quite a lot of useful information. If you look in their Technical Documentation database, you will find white papers, technical articles, and application notes.
Compared to a data sheet, the application note gives more details on how to use a technology (for example a chip or chip set) in different applications. They are quite handy as they tend to give some of those additional tips that you might have not come across in a text book.
A white paper is typically a more or less a scientific report with a marketing touch. (“Hey, look at us, we’re this clever!” – in a positive sense). In this context, the white papers are also supposed to educate the users of your product or technology, or at least brand your technology as much better than others’.
A tech article is in some sense quite similar to the white paper, but published in a more widely accessed media, like a magazine, which in our case could for example be the EE Times.
In addition to this, we have the scientific reports which are peer reviewed and published in more directed media, like the IEEE society journals and conferences.
Anyway, the ADI material is indeed good and most of them are conveniently short to be read and grasped quickly.
After some bed-time reading and browsing among the (as per today, 2012-01-20) 1479 articles, I decided to cut down to the Data Converters sections. Here we find 211 related to DACs and 379 to ADCs. (Hmm, why do ADCs always get more attention?). I guess it should be mentioned that the numbers are according to ADIs search engine with keywords “Analog to Digital Converters” and “Digital to Analog Converters”. Quite a few of the links are also broken, especially the older tech articles.
So, please find today’s top-ten list: The top-ten most useful ADI articles on data converters (and related). I’ll add a vote too and please, if you like, add your own favourite app note from ADI. We could also have a competition: who has the best app notes?
No particular order, and I have also bundled a couple of them since the topics were really close to each other. One could argue about the topics I’ve selected…
1) Specifications and other characteristics
A bit short perhaps, but at least adds some more information on parameters/specifications that should be taken into account when analyzing and choosing your data converters. Essentially, we do not only have the SNDR, SFDR, SNR, ENOB, etc. What else is important for the ADC?
Seven Steps to Successful Analog-to-Digital Signal Conversion (Noise Calculation for Proper Signal Conditioning), MS-2022
Matching An ADC To A Transformer
A couple of notes on how to interface your data converter. Both in terms of matching as such, but also how you should distribute noise, signal levels, etc.
Testing data converters
Understanding High Speed DAC Testing and Evaluation
Understanding High Speed ADC Testing and Evaluation, AN-835
Testing is always important. By reading these test documents you also get an insight in important parameters to test and how. This is beneficial in terms of design-for-test but also general design of your data converter.
This I like quite a lot. In my dissertation, I spent a lot of space on modeling of DAC converters and how to understand how different kinds of nonlinearities and irregularities show up in the output spectrum. This adds more value and is a way to understand how linearization of data converters can be implemented.
This is perhaps too few on sigma-delta converters. However, I picked this single – perhaps a bit too “simple” – to display here as it is a kind of eye opener for the additional design handles and options you have when dealing with sigma-delta modulators.
6) Sensor interfaces
Capacitance Sensors for Human Interfaces to Electronic Equipment
Building a reliable capacitive-sensor interface
Since I am quite much in to capacitive sensors currently with my body-area-network project, these two interesting articles caught my attention. ADI offers a capacitive-to-digital converter series and these two papers give an insight in how it works (and how it can be modified to support my work …)
7) Timing and sample related
Sampled Systems and the Effects of Clock Phase Noise and Jitter, AN-756
Little known characteristics of phase noise, AN-741
The power spectral density of Phase Noise and Jitter: Theory, Data Analysis, and Experimental Results, AN-1067
As indicated above, and also tought in pre-school, is that the jitter is a strong limitation on the obtainable performance in data converters. These application notes give a great view on jitter, it’s impact and how it can be investigated.
A couple of ideas on architectures and how they should be used. How should you pick your ADC given the system specifications. It is a non trivial task and potentially the paper leaves some questions unanswered.
Multi-channel ADCs of different kinds has proven (well …) to be one of the most promising ways to reach high performance and high speed. However, there are other error sources that need to be taken into account by then. For example aperture, offset, and gain mismatches between the different channels. This application note explains some of this (and gives and adequate set of references).
This is perhaps not doing justice here as it is quite an old paper (2001) and the role of the ADC (as explained) is now since long established. However, I would like here to tip you to check some of the forecast documents that ADI has produced, like 2011 Trends in Data Conversion, MS-2123-1 which is a snapshot of what’s hot related to data converters that year.