Is A/D-converter research becoming a purely academic exercise?

Figure 1. ADC research origin (first author). Absolute amount of papers.

Figure 2. ADC research origin (first author). Relative amount of papers.

Is A/D-converter research becoming a purely academic exercise? Well, looking at the statistics for scientific ADC implementation papers shown in the two graphs above, that certainly seems to be the future for open A/D-converter research. What are the implications, and does it matter?

Figure 1 shows the number of published ADC papers over time, separated into type of origin, as determined by the affiliation of the first author {Academic, Institute, Industry}. Although a simplification, it is believed to be a fairly accurate indication of where most of the work was done. The term Institute is referring to entities that are neither universities nor traditional companies, i.e., organizations like IMEC. Figure 2 shows the relative amount of contributions from each sector, based on the same data.

Where is corporate ADC research going?

Figure 2 paints a very clear picture: The industrial “market share” of scientific  publications has had a noisy but linear negative trend almost from the start. If the trend holds – and there are actually no signs in the graph that it won’t – there will be no scientific ADC papers from industry published after year 2020–2025! At least not with the first author being from the industry.

I find that quite remarkable and slightly counter-intuitive. Aren’t academic scientists the first to explore the un-explored, and after having spent a lot of time weeding out the less fruitful approaches, they finally come up with something that works? After which the industry wakes up and jumps on the bandwagon? The ADC field appears to do exactly the reverse: After initially been doing 100% of the work, the industry is now gradually letting the universities take over the field.

We are talking about the open research literature here, so it doesn’t necessarily mean that there is no activity within the companies. It just isn’t getting out. So, what do you think:

• Does the industry feel that there is nothing more to improve or research? If so, why can academic papers still get published?
• Is the industry increasingly putting a lid on their research to survive the competition?
• Or is it just a better business to focus on shifting parts, while letting universities innovate and then pick new solutions as they get published?

Quality – not quantity?

On the other hand, industrial contributions report excellent results. A state-of-the-art figure-of-merit (FOM) is a dream target for many research groups. In view of the dwindling industrial publication count, it is interesting to note that the performance of top industrial contributions does not seem to suffer: The overall best Thermal FOM for Nyquist converters was reported for a SAR design by Analog Devices [1], and the scientifically most sought-after world record “Walden FOM” was reported by a group of authors where three out of six were also affiliated with companies (Philips and Axiom IC) [2].

Poll

Additional info

The data set used is from an exhaustive survey [3] of ADC papers in journals and at conferences central to the field. After a recent update, the survey covers almost 1600 scientific papers or nearly all ADC implementations ever measured and reported scientifically since 1974. Hence the historical trends shown here should be definitive.

Want to know more?

Do you want to know more about ADC research trends? Are you making strategic decisions relating to data converter technology, research or business? The plots in Figure 1 and Figure 2 are taken from a larger report on ADC research trends that I’m currently working on for ADMS Design AB. The report will be available for purchase after the summer. It will survey ADC research trends from many different angles, and present valuable and truly unique information that is not offered anywhere else.

If you wish to be notified when the report is available, or want to know more, you can contact me at ADMS Design AB.

ADMS Design AB also offers full-custom surveys relating to commercial and scientific ADC trends, technology and business.

References

[1] C. P. Hurrell, C. Lyden, D. Laing, D. Hummerston, and M. Vickery, “An 18 b 12.5 MS/s ADC with 93 dB SNR”, IEEE J. Solid-State Circuits, Vol. 45, pp. 2647-2654, Dec., 2010.

[2]    M. van Elzakker, E. van Tuijl, P. Geraedts, D. Schinkel, E. Klumperink, and B. Nauta, “A 1.9μW 4.4fJ/Conversion-step 10b 1MS/s charge-redistribution ADC,” Proc. of IEEE Solid-State Circ. Conf. (ISSCC), San Francisco, California, pp. 244–245, Feb., 2008.

[3] B. E. Jonsson, “A survey of A/D-converter performance evolution,” Proc. of IEEE Int. Conf. Electronics Circ. Syst. (ICECS), Athens, Greece, pp. 768–771, Dec., 2010.

Is A/D-converter research in Europe about to die?

Number of scientific publications reporting measured A/D-converter implementations –by first-author affiliation location.

Is A/D-converter research in Europe about to die … or has it just gone into hiding? Well, looking at the publication statistics for measured ADC implementations justifies the question. In the overall publication count, there aren’t any signs of concern – Europe still has an accumulated 27% after North America’s 50% and before Asia’s 23% of all publications, as shown in a previous post. But Europe has lost a significant amount of wind in the last five years, which is obvious from the year-by-year stats shown in the plot. It seems that North America is maintaining its leadership in publications, but that Asia picked up some serious speed by 2006, while research publications from affiliations in Europe simultaneously dropped dramatically. North America and Asia both shows a steady increase, and note also that Asia has a steeper slope than North America. Europe is the only region that appears to level out at a lower publication rate. Why?

• Is Europe lacking the financial or intellectual muscle required to compete with North America and Asia?
• Is it a European view that the A/D-converter is a “commodity” that is best supplied from elsewhere and nothing of interest remains to be researched?
• Did European research “go into hiding” within companies and institutions that put a lid on their research results for commercial reasons? In that case, is the lack of publications merely a sign of good “industrial health”?
• Or has Europe simply lost its vision for ADC research?

What do you think? Share your thoughts and insights by leaving a comment or by taking the poll (multiple choices allowed).

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A few comments and remarks:

• The underlying data set is the same as in [1], but data for 2010 have been excluded since the results for 2010 are not settled yet. The main sources surveyed are listed here.
• Data and graphics is from a large ADC technology and research survey, and is courtesy of ADMS Design AB. (See also the ADMS Design pressroom for other results from the survey)
• Since I know a lot of people in Sweden and Europe that are active in ADC research, these results were surprising to me. My impression is (still) that there’s a lot going on in Europe, and therefore I would have expected all regions of the world to be increasing their publication rate.
• Obviously there are a lot of things to be said about how well a simple measure like “paper count” detects the research activity of a region. Nevertheless, there is a clearly different trend for Europe, and it does raise some interesting questions about what’s going on.

See also …

ADC Survey Data

References

[1] B. E. Jonsson, “A survey of A/D-converter performance evolution”, accepted for presentation, IEEE Int. Conf. Electronics Circ. Syst. (ICECS), Athens, Greece, Dec., 2010.

Who has done all that A/D-converter research?

ADC publication ‘power law’ curve: A handful of actors produce a lot, while the majority of organizations produce an accumulated total of one or two papers. Only papers reporting measurement results were included.

Of the approximately 1500 scientific papers covered in the ADC survey reported in [1]-[2] – also mentioned here, here, and used for the underlying data set here – who was actually responsible for all that work? Well … I could give you a complete list of author names – a very long list of names – but I’ll settle for a summary instead:

According to my data, there are about 270 different organizations that have at any time in history implemented, measured, and scientifically reported at least one A/D-converter IC. Now, that’s an average of five and a half papers per affiliation during the 36 years of monolithic A/D-converter integration [1].

But life isn’t that fair. In fact, there is no such thing as a representative average in this field. Instead, the publication count per organization roughly follows a power law curve as seen in the bar plot above. A few organizations (20–30) completely dominate the field, while a large number of organizations are represented by only one or two contributions.

I want to emphasize that there is absolutely nothing wrong with organizations that belong to the latter category. It’s fully possible (even likely) that these organizations deliver research results of the highest scientific quality – just that their focus is not on physical implementation. When looking at companies, one must also consider the possibility that a lot of activities may be going on “under the lid” for commercial reasons. But when it comes to publicly available research results, a relatively small group of actors have produced the majority of results, and among the top 30 there is an even distribution between companies and academic institutions. The top three affiliations are companies, and the following five bars represent the five most productive universities.

Note also that affiliation was determined from the first author of each paper and that work done at one affiliation is sometimes reported under the author’s current affiliation. I’ve tried to assess the true origin of the work as best I’ve could, e.g., by checking for affiliation footnotes showing past and present location. Since there is no way to know to what extent such information was always included when appropriate in all papers ever published since 1974, one must allow for some error margin here. And that’s one good reason to not start naming affiliations in this post.

Academic vs. corporate

ADC paper distribution between companies, universities, and “institutes”. Affiliation is determined by first author.

Instead we’ll check how the accumulated amount of ADC research papers divides between corporate and academic research? Not being really sure how to categorize some affiliations, I’ve introduced a third category, “Research Institutes”, for organizations that aren’t universities, but not classic companies either. In this category I have placed IMEC, ETRI, the Fraunhofer-Institute, ITRI, and the Space Research Institute. As illustrated by the pie chart, the total amount of scientific ADC papers published since 1974 divides into Academic (49%), Corporate (48%), and Institute (3%) when grouped by first author, and as much as 63% of the papers have at least one author affiliated with a company. A very strong impact from the corporate world, indeed.

Geographic region

Accumulated amount of ADC research papers by geographic region. Affiliation determined by first author.

Finally, we can look at the regional affiliation by continent: The accumulated total of ADC papers divide between North America (50%), Europe (~27%), Asia (~23%), and Africa (0.1%).

Africa is represented in my data by a single paper [3]. In comparison with North America, Europe, and Asia, a single paper may seem a bit slim. On the other hand it can be noted that, according to my data, Africa outperforms both South America and Australia, and that was not an obvious result – at least not for me.

Disclaimer: It is fully possible that I’ve missed some publications from these three continents, so please post references to them in your comments here if you know of any. Just remember that what I’ve counted here are papers about measured ADC implementations where the measurement results are reported in the actual paper or accompanying slides, and the continent scores according to the first author.

Now, didn’t this post make you at least a little bit curious? Don’t you start to ask yourself:

• Which are those top-3/5/10 affiliations?
• Which companies have given up on ADC research, and who are the new players that recently joined the game?
• What are the trends among companies/universities in North America/Europe/Asia?
• Is the whole world going in the same direction, or can we see any regional differences?
• What’s the average publication rate among the top five companies, and how does that compare to the top five universities?
• Are any of the top five slowing down or perhaps picking up an unusually strong wind?
• What’s happening to the pie slices – which ones are growing, and which ones are shrinking?
• Etc, etc …

Well … my boss (that’s me, actually) tells me I’ll need to save some information for ADMS Design AB and its clients too, but I will tell you something interesting in the next post nevertheless. You probably don’t want to miss that one if ADC research and development is your thing. So stay tuned …

Don’t forget: You can use the ‘Subscribe’ function to get an e-mail every time there’s a new post.

Edit: As mentioned here, this post is now cited in a scientific paper by Fuiano et al. [4]. Should you wish to do the same, you can cite it as suggested below [5].

See also …

ADC Survey Data

References

[1] B. E. Jonsson, “A survey of A/D-converter performance evolution”, accepted for presentation, IEEE Int. Conf. Electronics Circ. Syst. (ICECS), Athens, Greece, Dec., 2010. [@IEEE Xplore]

[2] B. E. Jonsson, “On CMOS Scaling and A/D-Converter Performance”, accepted for presentation, NORCHIP, Tampere, Finland, Nov., 2010 [@ IEEE Xplore]

[3] E. Hegazi, and N. Klemmer, “Accurate Modeling of Noise in Switched-C Analog-to-Digital Converters”, IEEE Trans. Circuit and Systems, Pt. I, Vol. 52, pp. 2319-2326, Nov., 2005.

[4] F. Fuiano, L. Cagnazzo, and P. Carbone, “Data Converters: an Empirical Research on the Correlation between Scientific Literature and Patenting Activity,” Proc. of Int. Workshop on ADC Modelling, Testing and Data Converter Analysis and Design (IWADC), Orvieto, Italy, June, 2011.

[5] B. E. Jonsson, “Who has done all that A/D-converter research?,” Converter Passion, Nov. 6, 2010, Available: https://converterpassion.wordpress.com