Multi-stage delta-sigma (ΔΣ) architectures, commonly known as MASH, are the preferred choice for analog-to-digital converters (ADCs) used in broadband communication applications, where high-resolution (above 14 bits) and high-bandwidth (several MHz) performances are required. Current state-of-the-art designs are capable of as much as 5-MS/s output data rates with 90-dB SNR. However,...
This thesis presents a novel algorithmic A/D converter to be used in a biosensor. The converter is capable of a conversion rate of 1.5 bits/phase and hence the required conversion time is reduced. The proposed architecture is analyzed for non-ideal effects and compared with existing algorithmic A/D architectures. The converter...
Evolution of the mobile communication standards and proliferation of hand-held devices mandate stringent Analog-to-Digital Converter (ADC) specifications. Among various ADCs, a ∆Σ ADC is best known as a power-efficient ADC when more than 12b is required. However, a conventional discrete-time (DT) ∆Σ Modulator (∆ΣM) is inadequate for low-power wideband applications...
Continuous process scale-down and emerging markets for low-power/low-voltage mobile systems call for low-voltage analog integrated circuits. Switched-capacitor (SC) circuits are the building blocks for analog signal processing and will encounter severe overdrive problems when operating at low voltage conditions. There exist three techniques to solve the problem, but with their...
Utilizing a two-capacitor topology, the digital implementation of an audio-band successive-approximation analog-to-digital converter (ADC) is explored in the context of mismatch-shaping where the mismatch estimates are accurate to the first order. A second-order Δ∑ loop was found to be effective in system simulations given a 0.1% capacitor mismatch. Spectral analysis...
Digital-to-analog converters (DACs) with wide dynamic range and high
linearity are required for high-end audio applications. A multi-bit delta sigma
audio DAC, using a novel gain-correction technique, is described in this thesis. For
widely varying on-chip RC time constant, the DAC gain can be accurately
controlled by the correction circuitry....
The design of mixed-signal integrated circuits has evolved from simple analog and digital circuits operating on the same silicon substrate to the point that now we have complete system on a chip solutions for communication systems. The levels of integration needed to remain cost effective in today's integrated circuit (IC)...
This thesis presents a continuous time bandpass delta sigma modulator with frequency translation inside the delta sigma loop. The input IF signal is down converted to baseband after amplification by a low Q, wideband bandpass resonator. The down converted IF signal is digitized by a continuous time, second order lowpass...
This thesis proposes a novel fully digital technique for the estimation and correction of the DAC error in multi-bit delta sigma ADCs. The structure of the DAC error is indicated through a simple model for unit-element based DACs. The impact of the DAC error on the performance of ADC is...
A novel switched-R-MOSFET-C input branch is proposed for low-voltage and high-linearity applications. The tunability is achieved by varying the clock duty cycle using an automatic tuning circuit. This tuning method does not involve a change in gate voltage, and is therefore particularly suitable for low-voltage applications. The advantages of the...