Posted: February 10, 2010

Imec and Holst Centre present 90nm CMOS ADC with record figure of merit suited for low- energy radios

(Nanowerk News) At today’s International Solid State Circuit Conference, IMEC and Holst Centre report an ultra-low power 8 bit analog to digital convertor (ADC) consuming only 30fJ energy per conversion step. This world-class figure of merit ADC is especially suited for upcoming low energy radios in the ISM (industrial, scientific and medical) radio bands such as low-energy Bluetooth or IEEE 802.15.6 for body-area networks.
Imec and Holst Centre realized this ultra-low power ADC with record performance by using a unique concept that combines a successive approximation (SAR) architecture working completely in the charge domain with an asynchronous controller. By doing all the charge redistribution passively, the power consumption of the SAR ADC is already drastically reduced compared to conventional SAR ADCs. An asynchronous controller is implemented to further minimize the power consumption and to allow operation on a single external sampling clock. This asynchronous implementation thus has no clock-driven precharge phase but instead self-synchronizes the various building blocks to maximize the speed of operation and to minimize the power consumption.
The chip was implemented in a 90nm digital CMOS technology. Measurements on silicon show a power consumption of only 69µW at a sampling rate of 10Msamples/s and a standby power of only 17nW. Since none of the ADC building blocks consumes any static power, the power consumption of the ADC scales linearly with the sampling frequency. Thus, the figure of merit of 30fJ/conversion step is maintained from 10kSamples/s to 10MSamples/s making it the widest power-efficient range published amongst comparable state-of-the-art designs.
“This result proves that imec and Holst Centre have built up extensive know-how in ultra-low power design within their program on ultra-low power radios for body-area networks. This extreme low-power ADC is applicable in ultra-low power radios usable in a wide range of applications from healthcare to industrial;” said Bert Gyselinckx, general manager imec the Netherlands at Holst Centre.
At this week’s International Solid State Circuit Conference, imec and Holst Centre present their newest breakthroughs in ultra-low power design for wireless communications and wireless sensor networks and in organic electronics with an impressive number of contributions including 10 reviewed publications and 6 contributions to tutorials and workshops.
This news release is based on paper 21.6: A 30fJ/Conversion-Step 8b 0-to-10MS/s Asynchronous SAR ADC in 90nm CMOS
About imec
Imec performs world-leading research in nano-electronics. 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 and Japan. Its staff of more than 1,650 people includes over 550 industrial residents and guest researchers. In 2008, imec's revenue (P&L) was 270 million euro.
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) and imec Taiwan (IMEC Taiwan Co.).
About Holst Centre
Holst Centre is an independent open-innovation R&D centre that develops generic technologies for Wireless Autonomous Transducer Solutions and for Systems-in-Foil. A key feature of Holst Centre is its partnership model with industry and academia around shared roadmaps and programs. It is this kind of cross-fertilization that enables Holst Centre to tune its scientific strategy to industrial needs.
Holst Centre was set up in 2005 by imec (Flanders, Belgium) and TNO (The Netherlands) with support from the Dutch Ministry of Economic Affairs and the Government of Flanders. It is named after Gilles Holst, a Dutch pioneer in Research and Development and first director of Philips Research.
Located on High Tech Campus Eindhoven, Holst Centre benefits from the state-of-the-art on-site facilities. Holst Centre has over 150 employees from around 25 nationalities and a commitment from over 20 industrial partners.
Source: imec