Thesis (Ph.D.) - Carleton University, 2002. / Includes bibliographical references (p. 136-146). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Carleton University, 2002. / Includes bibliographical references (p. 168-174). Also available in electronic format on the Internet.

Thesis (M. App. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 61-63). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 96-102).

Thesis (M.S.)--Rochester Institute of Technology, 2003. / Typescript. Includes bibliographical references (leaves 103-106).

Thesis (Ph. D.)--University of Rhode Island, 2006. / Includes bibliographical references (leaves 124-127).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

A modern system-on-chip (SoC) integrates a range of analog, digital, and mixed-signal building blocks, each with a dedicated voltage domain to maximize energy efficiency. On-chip low-drop-out regulators (LDOs) are widely used to implement these voltage domains due to their advantages of high power density and the ease of integration to a complementary metal-oxide-semiconductor (CMOS) process. Recently, digital LDOs have gained large attention for their low input voltage support for emerging sub-mW SoCs, portability across designs, and process scalability. However, some of the major drawbacks of a conventional digital LDO design are (i) the trade-off between control loop latency and power dissipation which demands a large output capacitor, (ii) failure to address the performance degradations caused by the parasitics in a practical power grid, and (iii) insufficient power-supply-rejection-ratio (PSRR) and large ripple in the output voltage. Chapters 2 through 4 of this thesis present my research on the design and circuit techniques for improving the aforementioned challenges in fully-integrated digital LDOs. The first work implements a hybrid event- and time-driven control in the digital LDO architecture to improve the response and settling time-related metrics over the existing designs. The second work presents a power delivery system consisting of 9 distributed event-driven digital LDOs for supporting a spatially large digital load. The proposed distributed LDO design achieves large improvements in the steady-state and non-steady-state performances compared to a single LDO design. In the third work, we prototype a digital LDO based on new current-source power-FETs to achieve a high PSRR and low output voltage ripple. Lastly, on-chip voltage regulators have recently found usefulness in hardware security applications. An on-chip LDO can be used to improve the side-channel attack (SCA) resistance of a cryptographic core with design modifications to the classical LDO architecture. However, the existing designs incur non-negligible overheads in performance, power, and silicon area due to the conventional active-for-all-encryption-rounds architecture. In the last chapter, we propose a detection-driven activation technique to achieve a near-zero energy-delay-product (EDP) overhead in a SCA resilient digital LDO. In this architecture, the LDO can detect an attack attempt and enable SCA protection only if an attack is detected.

The attempts at classification of functional faults in VLSI chips have not been very successful in the past. The problem is blown out of proportions because methods used for testing have not evolved at the same pace as the technology. The fault-models proposed for LSI systems are no longer capable of testing VLSI devices efficiently. Thus the stuck-at and short/open fault models are outdated. Despite this fact, these old models are used in the industry with some modifications. Also, these gate-level fault models are very time-consuming and costly to run on the mainframe computers. In this thesis, a new method is developed for fault modeling at the functional level. This new method called 'Model Perturbation' is shown to be very simple and viable for automation. Some general sets of rules are established for fault selection and insertion. Based on the functional fault model introduced, a method of test vector development is formulated. Finally, the results obtained from functional fault simulation are related to gate level coverage. The validity and simplicity of using these models for combinational and sequential VLSI circuits is discussed. As an example, the modeling of IBM's AMAC chip, the work on which was done under contract YD 190121, is described. / M.S.

High-speed digital to analogue converters (DAC), which are optimised for large bandwidth signal synthesis applications, are a fundamental building block and enabling technology in industrial instrumentation, military, communication and medical applications. The spurious free dynamic range (SFDR) is a key specification of high-speed DACs, as unwanted spurious signals generated by the DAC degrades the performance and effectiveness of wideband systems. The focus of this work is to enhance the SFDR performance of high-speed DACs. As bandwidth requirements increase, meeting the desired SFDR performance is further complicated by the increase in dynamic non-linearity. The most widely used architecture in high-speed applications is the current-steering DAC fabricated on CMOS technology. The current source finite output impedance, switch distortion and clock feedthrough are the greatest contributors to dynamic non-linearity and are difficult to improve with the use of MOS devices alone. This research proposes the use of BiCMOS technology that offers high performance, using heterojunction bipolar transistors (HBT) that, when combined with MOS devices, are able to improve on the linearity of the current-steering DAC and hence improve the SFDR. A design methodology is introduced based on BiCMOS fabrication technology to improve SFDR performance and places emphasis on the constraints of modern fabrication processes. A six-bit current-steering application-specific integrated circuit DAC is designed based on the proposed design methodology, which optimises the SFDR performance of high-speed binary weighted architectures by lowering current switch distortion and reducing the clock feedthrough effect to verify the hypothesis experimentally. A novel current source cell is implemented that comprises HBT current switches, negative channel metal-oxide semiconductor (NMOS) cascode and NMOS current source to overcome distortion by specifically enhancing the SFDR for high-speed DACs. A switch driver and low-voltage differential signalling receiver to achieve high-speed DAC performance and their influence on the SFDR performance are designed and discussed. The DAC is implemented using the International Business Machines Corporation (IBM) 8HP silicon germanium (SiGe) BiCMOS 130 nm technology. The DAC achieves a better than 21.96 dBc SFDR across the Nyquist band for a sampling rate of 500 MS/s with a core size of 0.1 mm2 and dissipates just 4 mW compared to other BiCMOS DACs that achieve similar SFDR performance with higher output voltages, resulting in much larger power dissipation. / Dissertation (MEng)--University of Pretoria, 2015. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted