Oversampling and noise-shaping methods for digital-to-analog (D/A) conversion have been widely accepted as methods of choice in high performance data conversion applications. In this thesis, the fundamentals of D/A conversion and oversampling D/A conversion were discussed, along with the detailed analysis and comparison of the reported state-of-the-art oversampling D/A converters. Conventional oversampling D/A converters use 1-bit internal D/A conversion. Complex analog filters and/or large oversampling ratios are usually needed in these 1-bit oversampling D/A converters. Using multi-bit internal D/A conversion, the analog filter can be much simpler and the oversampling ratio can be greatly reduced. However, the linearity of the multi-bit D/A converter has to be at least the same as that required by the overall system. The dual-quantization technique developed in the course of this research provides a good alternative for implementing multi-bit oversampling D/A converters. The system uses two internal D/A converters; one is single-bit and the other is multi-bit. The single-bit D/A converter is used in a path called the signal path while the multi-bit D/A converter is used in a path called the correction path. Since the multi-bit D/A converter is not directly placed in the signal path, its nonlinearity error can be noise shaped by an analog differentiator so that the in-band noise contribution from the nonlinearity error is very small at the system output, greatly reducing the linearity requirement on the multi-bit internal D/A converter. An experimental implementation of an oversampling D/A converter using the dual-quantization technique was carried out to verify the concept. Despite about 10 dB higher noise than expected and the high second-order harmonic distortion due to practical problems in the implementation, the implemented system showed that the corrected output had more than 20 dB improvement over the uncorrected output in both signal-to-noise ratio and dynamic range, demonstrating the validity of the concept. / Graduation date: 1996

This thesis describes the development of a flash analog-to-digital converter based on current-mode technique. The advantages of current -mode technique are higher speed, smaller chip area, and simple division of reference current based on current mirror. A current-mode comparator is designed consisting of a cascode current mirror and a current sense amplifier used as a latch. The new method allows effective and simple high-speed A/D conversion where the input is a current signal and the output of the latch is a digital voltage signal. A four-bit flash analog-to-digital converter, using current sense amplifier comparator is designed and simulated in 1-micron CMOS technology. Simulation results show that for ADC with resolution below six-bit, this technique offers a comparable accuracy with the existing voltage-mode methods at much higher speed. / Graduation date: 1993

Oversampled data converters are becoming increasingly popular for high-precision data conversion. There have been many publications on oversampled analog-to-digital (A/D) converters but relatively few on oversampled digital-to-analog (D/A) converters. In this thesis, issues concerning the analysis and design of the oversampled D/A converters are addressed. Simulation tools and analytical methods are discussed. A novel dual-quantization technique for achieving high-precision D/A conversion is proposed. A design example is presented to demonstrate that in many aspects the proposed technique is superior to existing techniques. The thesis is divided into four chapters. Chapter 1 is an introduction to the general concepts of Nyquist-rate and oversampled data converters. Chapter 2 describes some building blocks to be used in oversampled D/A converters and gives both theoretical and simulation methods for analzying them. Chapter 3 describes the proposed dual-quantization D/A converters, including the structure, the associated design issues and an example to verify the validity of this technique. Finally, Chapter 4 summarizes the properties of the simulated system and proposes some future research work. / Graduation date: 1992

This thesis presents the design of a 10 bit Analog to Digital Converter which consists of a 6 bit flash followed by a 4 bit pipeline architecture. The total system is described and the 4 bit pipeline is implemented on a bipolar process. The objective of this research is to provide an alternative approach to high speed ADC designs and to implement a pipeline ADC which samples at greater speeds than those achieved with presently existing CMOS pipeline designs. This paper presents the complete architecture, the cell design and simulated performance for each block in the pipeline, and the measured results for the four bit pipeline implementation. / Graduation date: 1993

In this paper, we present a low-power low-cost 6-bits, ADC using selective reference voltage technique. Using selective reference voltage technique, the different bit uses different comparator can be achieved. Meanwhile, the outputs from comparators are a binary code which can be used for generating logic condition thereby controlling the switches. Because the conventional n bits flash ADC requires 2n - 1 comparators and its power, area and input capacitance are all proportional to 2n - 1. Whereas, the proposed n bits ADC needs only n comparators which can save more power and area, and its input capacitance are proportional to n only, and keep high speed. Our proposed ADC is design by TSMC 1P6M 0.18£gm process with 6-bits resolution, 1.8V power supply. The signal input range 0.5V~1.1V, sampling rate 256MS/s, DNL +0.46LSB~ -0.49LSB, INL +0.85LSB~ -0.05LSB. In addition, the FOM of the ADC is only 0.26 pJ/Conv and the power consumption is only 4.2mW.It is good for a low-power and low cost customer electronic application.

Thesis (M.S. in electrical engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Feb. 9, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 42-43).

Licentiatavhandling Linköping : Linköpings universitet, 2009.

Thesis (M.S.) in Electrical Engineering--University of Maine, 2002. / Includes vita. Bibliography: leaves 94-95.

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