A high performance zero-crossing based pipelined analog-to-digital converter

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (leaves 46-47).In this thesis, I describe a zero-crossing based pipelined ADC. Unlike traditional pipelined ADCs, this work does not use any op-amps in the signal path. The use of zero-crossing based circuits made it possible to achieve a much better figure of merit. The ADC is design to operate at 200MS/s with a resolution of 12 bits. The simulated results suggest that the target performance is achievable with less than 10 mW of power. This design's figure of merit is at least an order of magnitude better than any existing designs that have comparable speed and accuracy performance. The design will be fabricated later to be tested in silicon.by Yue Jack Chu.S.M

High performance zero-crossing based pipelined analog-to-digital converters

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 133-137).As CMOS processes continue to scale to smaller dimensions, the increased fT of the devices and smaller parasitic capacitance allow for more power ecient and faster digital circuits to be made. But at the same time, output impedance of transistors has gone down, as have the power supply voltages, and leakage currents have increased. These changes in the technology have made analog design more difficult. More specifically, the design of a high gain op-amp, a fundamental analog building block, has become more difficult in scaled processes. In this work, op-amps in pipelined ADCs are replaced with zero-crossing detectors(ZCD). Without the closed-loop feedback provided by the op-amp, a new set of design constraints for Zero-Crossing Based Circuits (ZCBC) is explored.by Yue Jack Chu.Ph.D