Tag Archives: Connect with Converter Passion

Back from ECCTD 2011


After the crystal-clear scientific presentations at ECCTD, I'm now back in the mist again.

So, I’m back from ECCTD 2011 since late Wednesday, and up here at the southern edge of the northern half of Sweden, the mornings are misty and the leaves are turning yellow. Visiting Linköping was every bit as pleasant as I had expected. The conference was held at Linköping Konsert & Kongress, which is beautifully located at the center of the city, right next to the Linköping Cathedral.

The conference

The conference was excellently organized by the Electronics Systems division at Linköping University and the conference committee. I was particularly impressed with the student helpers. Not only were they helpful, kind and attentive, but quite a few of them also turned out to be passionate about data-converter research and development [one of the healthier states of the human mind, BTW 😉 ] and we had several interesting conversations on the topic. I couldn’t possibly have felt more welcome.

Professor Borivoje Nikolić speaks about managing variability.

After we all had been welcomed by the conference general chair, prof. Lars Wanhammar, Linköping University, the conference started with a plenary presentation “Managing Variability for Ultimate Energy Efficiency” given by prof. Borivoje Nikolić from UC Berkeley, USA. The conference then split up into various sessions which are described in detail in the program. ECCTD is a rather broad conference, but there were at least three dedicated data-converter sessions: “Sigma-Delta Modulators“, “Data Converters“, and “Pipelined ADCs“. I had the honor of chairing “Pipelined ADCs“, and I presented my own contribution “Area Efficiency of ADC Architectures” in the “Data Converters” session. I might come back to the content of that paper in another post, but in short (for those of you that were not there), it surveys the chip area vs. performance in speed and resolution for just about every ADC implementation reported in the scientific literature all the way since 1974 – approximately 1500 papers. A normalized area measure

A_{Q} = \dfrac{A}{{2}^{ENOB}}

was proposed based on the observed correlation between absolute chip area (A) and effective resolution (ENOB). State-of-the-art AQ – a.k.a. “Area per effective quantization step” – was seen to be independent not only of ENOB, but also of sampling rate over a broad range of sampling rates and resolutions, respectively. It is also approximately independent of CMOS process node. Chip area per effective quantization step was then compared for individual architectures, and design guidelines derived for area-optimal ADC architecture selection at any given speed and resolution specification. It was seen that there are large differences in the peak area efficiency achieved with different ADC architectures. There is for example a factor of 3 difference between SAR and pipeline, and a factor of 10 between pipeline and flash. Such big area differences can translate to a lot of money if you’re developing high-volume ADCs. So make sure you get hold of this paper as soon as it comes up on IEEE Xplore.

The blogger as session chair. Photo: Mark Vesterbacka

Professor Mark Vesterbacka, Linköping University had to push the electronics in his mobile phone to the maximum in order to document my chairing efforts in spite of the low light. Thanks for sending the picture.

CWCP winner

I could notice a slight peak in blog visitors yesterday. I assume that many of you wanted to know who won the Connect-with-Converter Passion (CWCP) prize, and I apologize for not being as fast as Dr. J Jacob Wikner who was blogging live from ECCTD and managed to fire away several conference-related post on Mixed-Signal Electronics while ECCTD was still developing. One of them correctly revealing that we had a CWCP winner already after the first day. And the winner is:

CWCP-winner Kiran Kariyannawar

Kiran Kariyannawar from Ericsson AB, who showed the enthusiasm and dedication necessary to win the CWCP prize for ECCTD. Congratulations Kiran! Kiran was there together with other Ericsson colleagues to demonstrate The Connected Tree and how to transmit audio and video signals through the human body. Quite far out compared to most demonstrations I’ve seen at scientific conferences. Very fun (at lest from a tech nerd’s perspective), and I’m sure they will figure out a lot of applications for it eventually, although for now they didn’t seem quite sure what to do with it. At least not with the connected tree. I played a bit with the human-body transmission (by becoming the channel), and I think it could be great for DJ-ing. I was just about to get it to rock big time when I started to realize the other delegates need for less noise and gave it up. If only I had a few more minutes to work out that groove …

The next big thing in DJ-ing? Just intermittently add a human body connected between those metal plates – preferably in a rhythmic pattern – and you're all set.

Other impressions

The conference dinner was held at the Air Force Museum – a place I’m likely to return to again to have more time to look at everything. Most likely with the rest of the family. A few photos below will give you some idea of the location. Finding unorthodox locations that can make the conference dinner extra memorable is probably a real challenge to most organizers. Unless they start taking us to outer space and back, I believe that the abundant food stations in combination with the breathtaking beauty of sea life shown at Monterey Bay Aquarium (ISCAS 1998) will remain my personal favorite for the rest of my life, but with ECCTD 2011 now being among the top two. Excellent work!

A classic Swedish beauty.

Chopper techniques. Large implementation.

A peaceful dinner ...

A missile of some kind, with a sign in Swedish saying "DO NOT PUSH HERE". Now, how irresistible is that on a scale to ten? Photo: M. Reza Sadeghifar

Having been to a few conferences, you start to recognize some faces that keep coming back. I had the pleasure of meeting delegates I’ve recently met. Some at NORCHIP, some at ICECS, and others at IWADC. It was great seeing you all. That is the real value of going to conferences.

Peace! 

ECCTD 2011 face-recognition. Note that we observed a severe Linköping bias here that might be compensated for in "future work".

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Connect with Converter Passion at ECCTD 2011


Hi all, and sorry about the low posting frequency during the summer. Now I’m here again, and this time to announce the Connect with Converter Passion (CWCP) competition for ECCTD 2011 next week. As always, I want to take the opportunity to connect with blog readers, and to give you some visibility.

Same face – new conference

To win the prize (which is the glory of winning + some visibility on this blog), all you need to do is to be the first one to locate me during the conference and claim the prize. Couldn’t be much simpler. Since the Linköping University group that is organizing the conference has a strong history of winning the CWCP prize, I will discriminate slightly against them this time (sorry guys) – but just slightly – to give the rest of you a fair chance. Affiliates of Linköping University will not be allowed to claim the prize until the second day of the conference (Tuesday). But don’t forget to try, because it may still be up for grabs by then.

If you haven’t located me before that, Tuesday is also a safe day to find me, as I’m presenting my ECCTD contribution “Area Efficiency of ADC Architectures” in session T21, Data Converters (starting 15:50). Last chance is around the W33 session, Pipelined ADCs, which I’ll be chairing on Wednesday afternoon.

Looking forward to seeing you in Linköping next week.

Connect with Converter Passion at IWADC 2011



Anyone planning to attend IWADC 2011 – the international workshop on ADC and data converters – in Italy the coming week?  Then make sure to connect, and you may win the Connect-with-Converter Passion prize for IWADC 2011. The reward is to have yourself mentioned here on the blog (see winners from last years NORCHIP and ICECS here and here), and the only thing you need to do to win is to be the first attendee to locate me during the conference and claim the prize. Besides announcing and introducing the winner of the CWCP,  I also plan to highlight a few interesting papers, pick up the conference “vibes” and share it in my reporting from the conference. I’ll be interested to talk to all of you, so even if you didn’t win the CWCP race I will be very happy to hear what you have to say about the conference, tech blogs, or the data converter field in general. What are your views on ADC FOM, the data converter market and scientific trends for the next decade, and more …

Look for this face

If you haven’t found me before, a safe bet is around the High-efficiency Data Converters session (Thursday 14:15–15:45) where I will present my first contribution An empirical approach to finding energy efficient ADC architectures , or at the Poster Session II for which I am chair on Friday, and where I will also present my second contribution Using Figures-of-Merit to Evaluate Measured A/D-Converter Performance. For more details, see the “Going to Italy, Yes, Yes, Yes!” post, and the conference program.

Back from ICECS 2010


The blogger (left) enjoying his lunch dessert together with Fahad Qureshi (middle), and the ICECS 2010 winner of the “connect-with-Converter-Passion” prize, Syed Ahmed Aamir (right). Photo: Currently unknown (email me).

Well, just being able to write “back from ICECS 2010” is a major victory, as the hundreds of scientists trying to come home from Athens may testify. Transportation strikes in Greece combined with unusual amounts of snow and bad weather clogging up several European airports at once, made the trip back home slightly more adventurous than usual. I managed to slip through most of the tight net created by these circumstances, and have realized from watching the news that the few bumps I encountered still left me as one of the lucky guys.

A winner!

Speaking of lucky guys: The clear winner of the “Connect-with-Converter Passion” race this time was Syed Ahmed Aamir, student at Linköping University, Sweden. Although nothing was set in stone, he showed all the signs of a winner already in this comment. Something that may have scared off most of the competition. In order to break the complete Linköping dominance in this race, I’m planning to not consider the local organizers (Linköping University) eligible for the prize if I go to ECCTD 2011. Either way, Aamir came to Athens to present his own paper “A 1.2-V Pseudo-Differential OTA with Common-Mode Feedforward in 65-nm CMOS”, and a paper by Armin Jalili Sebardan et. al – also from Linköping – entitled “Calibration of High-Resolution Flash ADCs Based on Histogram Test Methods”. Their colleague, Fahad Qureshi, presented the paper “Alternatives For Low-Complexity Complex Rotators”.

More ICECS delegates

A nasty cold forced me to rest more than planned, and that hampered my networking activities to some degree. I did however manage to see Dr. Skyler Weaver from Oregon State University presenting his paper “PDF Folding for Stochastic Flash ADCs”, and the poster “Asynchronous CLS for Zero Crossing Based Circuits” by OSU colleagues Hariprasath Venkatram, et al. Unfortunately for Dr. Weaver, we ended up at the same banquet dinner table in the beautiful Vorres Museum. Rather than enjoying his meal with a socially competent table-mate chatting about music, sports and the weather, his brain was contaminated all night long with my various views on ADC design, the correct use of ADC figures-of-merit and the likes. You can imagine the trauma … 😉

Skyler is obviously a man with a big heart and lots of patience.

View from the Chair: The five authors preparing for the session.

I also have to commend all five presenters in session W1L-B (Analog-to-Digital Converters II), for which I was chair: You all showed up with your presentations in good order, and you were very disciplined staying within your time-slots. Your reward will be a slightly raised web presence by having your work highlighted here. The complete session was:

  1. Column Parallel Single-Slope ADC with Time to Digital Converter for CMOS Imager”, presented by Muung Shin from Hokkaido University, Japan.
  2. A Digital Processor for Full Calibration of Pipelined ADCs”, presented by Dr. Javad Frounchi from University of Tabriz, Iran.
  3. Comparison of DEM and BEET Linearization Techniques for Flash Analog-to-Digital Converters Using a SFDR Metric”, presented by Christopher D. McGuinness from University of Dayton Research Institute.
  4. An Ultra Low Power 9-bit 1MS/s Pipelined SAR ADC for Bio-medical Applications”, presented by Guohe Yin from University of Macau, China.
  5. Mismatch Aware Power and Area Optimization of Successive-Approximation ADCs”, presented by Jia Mao from Royal Institute of Technology, Stockholm, Sweden.

As previously shown, there were around 27 ADC-related papers altogether, and I’m not going to list them all here. You will soon find the entire proceedings on IEEE Xplore, and I don’t want to spoil all the fun by telling everything about the conference. As always, the comment field below is open for you to add your own views and comments. If you want to highlight any other paper, participant or author, just go ahead and do it. By all means, promote your own work too! Don’t be shy …

Enjoy the output of your own research field: Nifty proceedings and gadgets.

ICECS 2010 Proceedings and some final thoughts

I know it’s probably getting commonplace by now, but I still can’t help but liking the design and implementation of conference proceedings also this time: A pen, laser pointer and USB memory all in one. Very practical indeed, and I’m still dwelling on the fact that with proceedings like these we’re reaping the benefits of our own research in microelectronics.

Some of you have been mentioned above, but I met many other delegates that in one way or another made ICECS 2010 a memorable event. Thank you all for novel ideas, a kind smile, a good chat during coffee breaks, and for nice company at the tables. You know who you are. Makes yourselves known to the world by posting a greeting below.

Also, if you have anything you want to ask about my paper “A Survey of A/D-Converter Performance Evolution”, or want to add anything to what I’ve written above, feel free to do so in your comments.

Finally, I haven’t decided yet what conference(s) to go to next – in case you’re wondering about the next opportunity to win the connect-with-CP prize. Both ECCTD 2011 and the 2011 IMEKO IWADC & IEEE ADC Forum have showed up on my radar looking good. Why not check them out?

BTW:

Back from NORCHIP


This is what coming home looked like for me on the first day after the conference (click on photo to enlarge). Lake Dellen is about to freeze. As I already told some of you at NORCHIP, I don’t live close to the nature – I live IN the nature. The barn hinted in the distance belongs to the small farm where I live. A trace of civilization and wireless infrastructure is found on top of the distant mountain. And … we have electricity too ☺.

OK, I’m back from NORCHIP since two days. I utterly failed to blog ‘live’ from the conference as I intended to. It was simply too many interesting persons to meet and presentations to hear for me to have any time for blogging. And the photo of the banquet dish that I promised as compensation failed too because of the relaxed darkness of the restaurant in which it was served. Needless to say I will not make promises like that when I go to ICECS next month, although my intention is to blog about that conference too. NORCHIP is “the Nordic microelectronics event“, so the conference is smaller than for example a European conference like ESSCIRC or ICECS, but there’s no lack of interesting people to connect with. In fact, I believe that the smaller format rather improves your chances of actually finding some time to talk to senior delegates and other people you’d like to exchange ideas with. I enjoyed the conference a lot, and below I’ll highlight a few contributions and delegates that come to mind. And, don’t be shy! If you’re not mentioned here, just post a comment below.

Professor Yong Lian

Professor Yong Lian, National University of Singapore (NUS),  gave an invited speech titled “Towards Self-Powered Biomedical Devices”. His presentation contained many interesting technical details and also left me with a feeling that it is really exciting to be in microelectronics research because there are still so many interesting topics to investigate.

A significant part of my career has revolved around calibration of A/D-converters. I therefore listened with great interest to the invited speech “Purely-Digital versus Mixed-Signal Self-Calibration Techniques in High-Resolution Pipeline ADCs” by professor João Goes from Universidade Nova de Lisboa (UNL) . A review of different techniques to calibrate pipeline ADCs.

Data conversion contributions

Nadeem Afzal

Meeting the future of data-converter science, as represented by the current generation of Ph.D. students, was also rewarding. Nadeem Afzal from the Electronics Systems division, Linköping University, Sweden was the first to respond to my previous invitation to connect, and he was soon followed by his colleague M. Reza Sadeghifar. Their contributions were titled: “Study of Modified Noise-Shaper Architectures for Oversampled Sigma-Delta DACs”, and “A Higher Nyquist-Range DAC Employing Sinusoidal Interpolation”, respectively.

Other data-converter contributions during the first day were “Effects of Filtering on the Linearity of Current-steering IF DAC”, presented by Timo Rahkonen, University of Oulo, Finland, “A Low-Power, Medium-Resolution, High-Speed CMOS Pipelined ADC” by Deivasigamani Meganathan, Madras Institute of Technology, India, and “A New DFT based Approach for Gain Mismatch Detection and Correction in Time-Interleaved ADCs” by Yashar Hesamiafshar, University of Tehran, Iran.

M. Reza Sadeghifar

On the second day of the conference there was more: “Calibration of ΣΔ Analog-to-Digital Converters Based on Histogram Test Methods” by Armin Jalili, Isfahan University of Technology, Iran, “A Second-Order Low-Power ΔΣ Modulator For Pressure Sensor Applications” by Tero Nieminen, Aalto University, Finland, and “An 8-bit 166nw 11.25 kS/s 0.18um two-Step-SAR ADC for RFID applications Using Novel DAC Architecture” by Iman Kianpour, Sabzevar Tarbiat Moallem University, Iran.

The conference was rounded off on the second day with the A/D-converters session where my own presentation “On CMOS Scaling and A/D-Converter Performance” was scheduled. The three other papers in our session were a second paper by Tero Nieminen, Aalto University, Finland, “An 1.2V 440-MS/s 0.13-μm CMOS Pipelined Analog-to-Digital Converter With 5-8bit Mode Selection”, “A 290μA, 3.2MHz 4-bit Phase ADC for Constant Envelope, Ultra-low Power Radio” by Budhaditya Banerjee, CSEM, Switzerland, and “Design of CMOS Sampling Switch for Ultra-Low Power ADCs in Biomedical Applications” by Dai Zhang, Linköping University, Sweden.

Unfortunately I barely managed to stay within the 20 min time slot for my paper, which didn’t leave much room for questions afterwards. So, if you have any questions on the content of my paper that you didn’t ask then you can ask them here instead. A few notes on the above:

  • For brevity, the names and affiliations listed above are the first authors or presenters of each paper only – just like the conference program. If you wish to share your credit by highlighting coauthor names & affiliations you are very welcome to do so by posting a comment below.
  • Some names/affiliations are left without clickable links because I couldn’t find a web domain (email) in the paper header, or the author’s personal web page at the institution. If you want, you can e-mail me the URL, and I’ll make an update so that readers can find you more easily.
  • If there is any ADC/DAC paper that I failed to mention, or if you feel that I have misrepresented you or your affiliation in any way, just send me an e-mail, and I’ll correct it.
  • Even if you didn’t go to NORCHIP this year, you will eventually find all the papers on IEEE Xplore. Edit: NORCHIP 2010 is now available on IEEE Explore here, and if you specifically want to check out my paper, start here.

Other impressions from NORCHIP 2010

Microelectronics scientists enjoy the fruit of their own labour. Thanks to the research in our own field, the size of conference proceedings is now about 25% of the conference badges.

I want to particularly thank anyone involved in memory research for the technology enabling us to have conference proceedings that are 25% the size of our conference badges. Effectively, it means that we are enjoying the fruits of our own research as it makes our conferencing more comfortable. On the other hand, the NORCHIP proceedings were never close to the 3–6 volumes a typical ISCAS could produce, so maybe it wasn’t such a big difference for everyone. Nevertheless, I liked it. And … it does make a huge difference for the conference coordinator since 1985, Ivan Ring Nielsen, Technoconsult ApS, Denmark, who introduced the USB proceedings in 2007. He no longer has to lug around 60–100kg of printed proceedings every year, and instead of paying excessive-weight charges to airlines, he can now invest all that extra money in the conference food budget 🙂

Food is the "hub" of networking

Scientific efforts tend to make you really hungry, so an important aspect of any conference is the food. Not only the banquet dinner, but also the lunches, coffee breaks and snacks. The “hub” of conference networking is to a large degree the opportunity to talk to each other during coffee, lunch and dinner breaks, so it should be good. And it was. I can highly recommend Scandic Tampere City for conferences of a similar format. Excellent job! The salad bar at lunch time was one of my favourites. Because of all the nice offerings, I filled my plate to 80% with veggies, leaving space only for a tablespoon or two of the main dish. I am a die-hard red meat lover that think the green stuff is best used to feed the critters I hope to grill sometime in the future, so that was a very high rating for the salad bar.

Mixed seeds sounds good for ADC/DAC folks

Poster sessions blend particularly well with coffee breaks, and what could be a better snack for data-converter designers than “mixed seeds”? I assume the large green seeds must be the analog, and the small white seeds the digital that shrunk with process scaling.

Faithful readers of this blog will have figured out by now that I love pie charts almost as much as I love pie, and if you have read this far you may be wondering if I’m not going to serve you any pie chart in this post. Yes, I will!

In case anyone is curious about the delegates you can expect to meet at NORCHIP 2011 in Lund next year, I’ve compiled a pie-chart showing the country of affiliation for this years NORCHIP delegates (from the official list of participants). As expected, it appears that a majority of delegates are from affiliations in Finland, Norway and Sweden, but delegates came from as far away as Iran, India, Singapore, Japan, and USA. And before signing up for a crash course in casual conversation using Scandinavian languages, you may want to consider that research knows few boundaries, and therefore the country of affiliation does not always reflect the nationality of the participant. In fact, the fast growth of research in Asia discussed in the previous post is clearly evident also from the many visiting Ph.D. students in Nordic countries, and just as visible at NORCHIP.

NORCHIP is therefore a much more international event than its label reveals.

NORCHIP 2010 delegate distribution by country of affiliation