Illinois researchers win chip design award

ECE Assistant Professor Yun Chiu and PhD student Wenbo Liu recently presented a parallel analog-to-digital converter (ADC) array chip at the International Solid-State Circuits Conference (ISSCC) that won them the 46th DAC/ISSCC Student Design Contest Award.

Describing the significance of their winning chip, Chiu explained that many people in the computing field have most likely heard a lot about parallelizing future digital computing with multicore processors. At Illinois, the excitement is also happening for analog integrated circuits.

The research was based on a new idea developed by Chiu. To obtain higher speed or bandwidth for digitization, one approach is to have a single ADC that operates on a faster clock. Alternatively, many slow ADCs can be used at the same time. The technical challenge then is how to line up the analog performance of these time-interleaved converters, which are very sensitive to process, temperature, and supply voltage variations. “We don’t touch much on the analog part. Its performance isn’t better than plain digital circuits,” said Chiu, “We’re casting the conventional analog wisdoms out of the window. Instead, you run cheap, energy-efficient digital circuits in the back end, and they help to detect and correct for analog errors or defects.” In their work, Chiu and Liu applied an adaptive digital equalization algorithm from communications that helps to compensate impairments in the analog circuits.

Though the chip may be fast, the research that went into it was more time consuming. “One thing people tend to overlook is how much time it takes to build highly complex integrated circuit chips these days in nano-scale silicon technology.” Their award-winning paper was the result of nearly 3 and a half years research and work done by Liu.

Chiu said he and Liu are both thrilled to win, especially an award at DAC/ISSCC. “This is the kind of award you want to win if you are working in integrated circuits or CAD [computer-aided design] areas,” said Chiu, “Both are indeed the leading internationally renowned conferences in these areas.”

Their paper was first submitted, accepted, and presented by Liu at the ISSCC in February. Chiu said that winning this award has more positive implications than simply being recognized by the IC community. It means that the University has been recognized for its cutting-edge IC research. Chiu said that having papers published will bring more recognition to Illinois.

 “I think that [presenting] at ISSCC is a great leap for us, and I hope this trend will continue in the coming years,” said Chiu. “We want to try and win as many awards as we can. There is a consensus among the circuits faculty here, and we’re all working very hard on it.”