Self-Calibrated 10 Mbit/s Phase Modulator with Low Power fractional PLL Architecture Exceeding State-of-the-Art Performance

Leuven, Belgium – Feb. 3, 2016 – At this week’s IEEE International Solid-State Circuits Conference (ISSCC2016), nanoelectronics research center imec and Vrije Universiteit Brussel (VUB) presented a self-calibrated high-speed (10Mbits/s) phase modulator achieving an excellent Error Vector Magnitude (EVM) of -37dB at 10.25 GHz. The modulator is based on a l analog fractional subsampling PLL featuring a world leading -246.6dB Figure of Merit (FOM). It is an attractive solution for phase modulation in highly efficient polar transmitters.

Radio frequency synthesizers are ubiquitous building blocks of today’s ever growing networking solutions. Whether for high throughput applications like LTE-Advanced or for sub-mW Internet-of-Things nodes, the phase noise of the RF synthesizer sets a limit to the achievable data rate or to the total radio power consumption, as one can often be traded for the other. On top of that, for efficient spectrum usage, the new standards typically involve higher order modulation schemes. Polar transmitters, using efficient nonlinear power amplifiers might be a good option, but they need highly accurate phase modulators.

The PLL is built around an analog-based subsampling high-gain phase detector, which enables low-noise operation. The advanced 28nm CMOS technology is exploited to enhance its performance through innovative built-in background self-calibration that corrects all non-idealities of the analog building blocks. Together, these technique ensure a state-of-the-art noise performance resulting in only 176fsec jitter. Similarly, digital phase modulation is implemented, with quasi-ideal performance thanks to background calibration of all non-idealities. Combined with the intrinsic low noise of the PLL, a record EVM better than -37dB is achieved at 10GHz carrier.

These results were presented at ISSCC2016 as paper 9.7 in the High performance wireless session: “N. Markulic et al.; A Self-Calibrated 10Mb/s Phase Modulator with -37.4dB EVM Based on a 10.1-to-12.4GHz, -246.6dB-FOM, Fractional-N Subsampling PLL.”

About imec

Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, US, China, India and Japan. Its staff of more than 2,300 people includes almost 700 industrial residents and guest researchers. In 2014, imec's revenue (P&L) totaled 363 million euro. Further information on imec can be found at www.imec.be. Stay up to date about what’s happening at imec with the monthly imec magazine, available for tablets and smartphones (as an app for iOS and Android), or via the website www.imec.be/imecmagazine
Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a "stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.) and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited).

About VUB

Vrije Universiteit Brussel, in the heart of Europe
Over 14,200 students, representing more than 120 nationalities study at VUB to take the next step in their career. 3000 of our students – more than 21% of our student population - are international students, making our institute a vibrant and truly global one.

VUB supports more than 100 English-taught programs with both outstanding research and a modern campus. Everything you need is at your fingertips and available on-site, near Brussels' bustling city center: an extensive library, modern computer labs, state-of-the-art sports facilities, and exciting restaurants as well as interesting cultural activities, language courses and an invaluable job service.

In VUB's eight faculties, students can choose to study and explore beyond their own discipline where they can exchange experiences, cultures, ideas and values. The University's open-door policy means students build rapport with both faculty members and assistants, and staff are happy to answer student questions. Small group workshops are also in place to provide close interaction and hands-on experience.

Thanks to its expertise and location in Brussels, VUB is an ideal partner for prestigious research and education with an outlook on Europe and the world. With a research budget of EUR 86 Million, VUB covers some 2,200 publications and 24 reported inventions annually, supporting 150 research groups.

VUB is a haven for education and research, combining the best of both on American-style green campuses. It is listed in the top 200 QS World University Ranking and 251 – 275 in the Times Higher Education Ranking. The university has more than 75 cooperation contracts in 38 countries. It offers postgraduate degrees in English and awards Bachelor’s and Master’s degrees in a range of academic fields covering human sciences, life sciences and medicine, sciences and engineering. Doctorates are offered in all subjects for which the university issues academic degrees. VUB counts more than 1,800 PhD students.