Identifier

etd-11052011-182642

Degree

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

Document Type

Dissertation

Abstract

Phase-locked loops (PLLs) have been widely used in mixed-signal integrated circuits. With the continuously increasing demand of market for high speed, low noise devices, PLLs are playing a more important role in communications. In this dissertation, phase noise and jitter performances are investigated in different types of PLL designs. Hot carrier and negative bias temperature instability effects are analyzed from simulations and experiments. Phase noise of a CMOS phase-locked loop as a frequency synthesizer circuit is modeled from the superposition of noises from its building blocks: voltage-controlled oscillator, frequency divider, phase-frequency detector, loop filter and auxiliary input reference clock. A linear time invariant model with additive noise sources in frequency domain is presented to analyze the phase noise. The modeled phase noise results are compared with the corresponding experimentally measured results on phase-locked loop chips fabricated in 0.5 m n-well CMOS process. With the scaling of CMOS technology and the increase of electrical field, MOS transistors have become very sensitive to hot carrier effect (HCE) and negative bias temperature instability (NBTI). These two reliability issues pose challenges to designers for designing of chips in deep submicron CMOS technologies. A new strategy of switchable CMOS phase-locked loop frequency synthesizer is proposed to increase its tuning range. The switchable PLL which integrates two phase-locked loops with different tuning frequencies are designed and fabricated in 0.5 µm CMOS process to analyze the effects under HCE and NBTI. A 3V 1.2 GHz programmable phase-locked loop frequency synthesizer is designed in 0.5 μm CMOS technology. The frequency synthesizer is implemented using LC voltage-controlled oscillator (VCO) and a low power dual-modulus prescaler. The LC VCO working range is from 900MHz to 1.4GHz. Current mode logic (CML) is used in designing high speed D flip-flop in the dual-modulus prescaler circuits for low power consumption. The power consumption of the PLL chip is under 30mW. Fully differential LC VCO is used to provide high oscillation frequency. A new design of LC VCO using carbon nanotube (CNT) wire inductor has been proposed. The PLL design using CNT-LC VCO shows significant improvement in phase noise due to high-Q LC circuit.

Date

2011

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Srivastava, Ashok

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