A Power Scalable and Low Power Pipelined ADC [chapter]

Imran Ahmed
2010 Pipelined ADC Design and Enhancement Techniques  
A 10-bit pipeline Analog-to-Digital Converter (ADC) is designed such that its average power is scaleable with sampling rate over a large variation of sampling rates. Fabricated in CMOS 0.18μm technology, while having an area of 1.21mm 2 , the ADC uses a novel fast Power Resettable Opamp (PROamp), to achieve power scalability between sampling rates as high as 50Msps (35mW), and as low as 1ksps (15μW), while having 54-56dB of SNDR (at Nyquist) for all sampling rates. A current modulation
more » ... is used to avoid weakly inverted transistors for low bias currents, thus avoiding less accurate simulation, poorer matching, and increased bias sensitivity. The PROamp due to its short power on/off time also affords reduced power consumption in high speed pipeline ADCs, where opamps can be completely powered off when not required. Measured results show an ADC using PROamps has 20-30% less power than an ADC which does not use PROamps. iv v Acknowledgements Researching a thesis is a unique proposition. One is forced to look into the depths of the unknown and find an answer to a question that does not necessarily have an answer. In some cases your answer fits the question -in some cases your answer fits the question like a square peg in a round hole. Regardless of the maddness, the journey of developing a thesis from abstract ideas to ultimately a functional prototype is truly a unique and completely enriching experience -an experience that I for one am tremendously thankful for and very fortunate to have undergone. Acknowledging specific people in the development of an abstract piece of art as a thesis is somewhat partial, as undoubtedly every person one interacts with during the course of a thesis in some shape or form impacts the work. There are few however who have helped this piece of abstract art take form. Of course firstly I must thank my supervisor, Professor David Johns. No doubt without his aid in developing the focus of this work, and his invaluable suggestions and advice throughout the duration of this degree, this work would not have been possible. Next I am tremendously indebted to the aid and friendship of the 'Master's crew', of Navid, Rob, and Trevor who in addition to helping me develop and refine my skills as a mixed-signal designer, have made my tenure as a Master's student at U of T, truly enriching and thoroughly enjoyable. There are of course others who shall remain nameless, whose support and encouragement during the lows of lows and highs of highs was both welcome and much needed. Inspiration can come from surprising sources -a wise researcher should always be aware of this. Of course one cannot accomplish anything in life without the unquestioned pillar of support one's family offers. To my family I dedicate this work, for whom without I would not be where I am today. vi vii
doi:10.1007/978-90-481-8652-5_7 fatcat:2s7yeyvqonhrpdvhxqseowxwl4