In this work, a fully differential Operational Amplifier (OpAmp) with high Gain-Bandwidth (GBW), high linearity and Signal-to-Noise ratio (SNR) has been designed in 65nm CMOS technology with 1.1v supply voltage. The performance of the OpAmp is evaluated using Cadence and Matlab simulations and it satisfies the stringent requirements on the amplifier to be used in a 12-bit pipelined ADC. The open-loop DC-gain of the OpAmp is 72.35 dB with unity-frequency of 4.077 GHz. Phase-Margin (PM) of the amplifier is equal to 76 degree. Applying maximum input swing to the amplifier, it settles within 0.5 LSB error of its final value in less than 4.5 ns. SNR value of the OpAmp is calculated for different input frequencies and amplitudes and it stays above 100 dB for frequencies up to 320MHz. The main focus in this work is the OpAmp design to meet the requirements needed for the 12-bit pipelined ADC. The OpAmp provides enough closed-loop bandwidth to accommodate a high speed ADC (around 300MSPS) with very low gain error to match the accuracy of the 12-bit resolution ADC. The amplifier is placed in a pipelined ADC with 2.5 bit-per-stage (bps) architecture to check for its functionality. Considering only the errors introduced to the ADC by the OpAmp, the Effective Number of Bits (ENOB) stays higher than 11 bit and the SNR is verified to be higher than 72 dB for sampling frequencies up to 320 MHz.

This work deals with the influence of MDAC (multiplying DAC) resolution on basic blocks of pipelined AD converter. The MDAC was designed with 1,5 and 2,5 bits resolution structure using switched capacitor technique (SC) utilizing CMOS 0,7 m technology. Basic stages of this pipelined ADC are analyzed and compared.

Tato diplomová práce se zabývá návrhem 12 bitového řetězového A/D převodníku. Součástí návrhu bylo vytvořit referenční model převodníku v prostředí Matlab a determinovat faktory, které negativně ovlivňují výsledek konverze. S využitím nabytých poznatků navrhnout řetězový převodník na transistorové úrovni v prostředí Cadence. V teoretické části jsou shrnuty základy A/D převodu a dále jsou představeny nejčastěji používané architektury A/D převodníků. V dalších částech je popsán a diskutován vliv neidealit na vlastnosti řetězových převodníků. Praktická část se již věnuje popisu základních charakteristik řetězových převodníků a dokazuje funkci modelu. Z výsledků modelové struktury byly stanoveny reálné parametry, které byly dále využity v procesu tvorby návrhu v CMOS technologii TSMC 0,18m s nízkým napájecím napětím.

Numerous techniques are used to study the magnetic history and properties of rocks, which provides important data on the Earth’s interior. In this study we conducted a series of experiments on two different sample sets, comprising pure magnetite (Set1) and a mixture of magnetite-hemoilmenite-bearing quartzite (Set2), in order to gather information about their magnetic susceptibility and remanent magnetization. A miniature diamond anvil cell (mDAC) constructed from hardened non-magnetic alloy (40HNU) was used for high pressure experiments. With the help of high sensitivity susceptibility bridge (MFK1-FA Kappabridge, AGICO), we measured the susceptibility of three samples and of the mDAC. Consequently, we loaded one of the samples in the mDAC and acquired susceptibility measurements during the compression and decompression of the system. For remanence measurements we used a 2G Enterprises SQUID magnetometer. We measured the natural remanent magnetization (NRM) and performed alternating field (AF) demagnetization on ten samples and on the mDAC. Additionally, isothermal and anhysteretic remanent magnetization (IRM and ARM) acquisition were performed on nine and one samples, respectively and demagnetization on three and one samples, respectively. Results showed that Set1 samples consist of both SD and MD magnetite grains. Regarding Set2 samples, the main magnetic carriers are SD and MD magnetite or titanium bearing magnetite grains, while there are indications that hematite and ferrimagnetic titanohematite might be present as well. The presence of eddy currents, due to the conducting materials of the mDAC, resulted in masking the signal of the sample making it difficult to draw any safe conclusions regarding how the susceptibility of the sample changes with pressure. All in all, there was a satisfactory response of the instruments working with very small amounts of material and an adequate signal stability of both the samples and the mDAC. Our study provided us with an insight into high pressure experiments and showed possible directions for future studies. / Många metoder används för att studera magnetiska egenskaper i berg, vilket ger viktig information om Jordens inre. I denna studie genomförde vi en rad experiment på två olika uppsättningar prov, innefattande ren magnetit (Set1) och en blandning av magnetit-hemoilmenit-bärande kvartsit (Set2), för att samla information om deras magnetisk susceptibilitet och magnetiska remanens. En miniatyr diamantstädcell (mDAC) konstruerad av en härdad icke-magnetisk legering (40HNU) användes för högtrycksexperiment. Susceptibilitetet av tre prover och av mDAC mättes en MFK1-FA Kappabridge, AGICO. Följaktligen monterade vi ett av proverna i mDAC och vi genomförde susceptibilitetsmätningar under kompression och dekompression. Vi använde en 2G Enterprises SQUID magnetometer för remanensmätningar. Den naturlig remanentmagnetiseringen (NRM) mättes och vi utförde alternerande fält (AF) demagnetisering på tio prover och på mDAC. Dessutom genomfördes isotermisk och anhysteretisk remanentmagnetisering (IRM och ARM) på nio respektive ett prover, och demagnetisering på tre respektive ett prover. Resultaten visade att Set1-prover består av både enkeldomän (SD) och multidomän (MD) magnetit. SD och MD magnetit- och titanomagnetitkorn är de viktigaste magnetiska mineral av Set2-prover, medan finns det indikationer på att hematit och ferrimagnetisk titanohematit också bidrar till signal. Virvelströmmar, som skapats av mDACs ledande material, maskerade provets magnetiska susceptibilitet och det var svårt att kommentera på hur provets susceptibilitet förändras med tryck. Sammantaget var instrumentens prestanda tillfredsställande, även vid små mängder material. Prov och mDACs signalstabilitet var också adekvat. Vår studie gav oss en inblick i högtrycksexperiment och magnetiska egenskaper och den visade möjliga riktningar för framtida studier.

<p>In order to convert the analog information in the digital domain, pipelined analog-to-digital converter (ADC) offers an optimum balance of resolution, speed, power consumption, size and design effort.</p><p>In this thesis work we design and optimize a 8-bit pipelined ADC for low-power. The ADC has stage resolution of 1.5-bit and employ current mode multiplying analog-to-digital converter (MDAC). The main focus is to design and optimize the MDAC. Based on the analysis of "On current mode circuits" discussed in chapter 2, we design and optimize the MDAC circuit for the best possible effective number of bits (ENOB), speed and power consumption. Each of the first six stages consisting of Sample-and-Hold, 1.5-bit flash ADC and MDAC is realized at the circuit level. The last stage consisting of 2-bit flash ADC is also realized at circuit level. The delay logic for synchronization is implemented in Verilog-A and MATLAB. A first order digital error-correction algorithm is implemented in MATLAB.</p><p>The design is simulated in UMC 0.18um technology in Cadence environment. The choice of technology is made as the target application for the ADC, 'X-ray Detector System' is designed in the same technology. The simulation results obtained in-term of ENOB and power consumption are satisfactory for the target application.</p>

In order to convert the analog information in the digital domain, pipelined analog-to-digital converter (ADC) offers an optimum balance of resolution, speed, power consumption, size and design effort. In this thesis work we design and optimize a 8-bit pipelined ADC for low-power. The ADC has stage resolution of 1.5-bit and employ current mode multiplying analog-to-digital converter (MDAC). The main focus is to design and optimize the MDAC. Based on the analysis of "On current mode circuits" discussed in chapter 2, we design and optimize the MDAC circuit for the best possible effective number of bits (ENOB), speed and power consumption. Each of the first six stages consisting of Sample-and-Hold, 1.5-bit flash ADC and MDAC is realized at the circuit level. The last stage consisting of 2-bit flash ADC is also realized at circuit level. The delay logic for synchronization is implemented in Verilog-A and MATLAB. A first order digital error-correction algorithm is implemented in MATLAB. The design is simulated in UMC 0.18um technology in Cadence environment. The choice of technology is made as the target application for the ADC, 'X-ray Detector System' is designed in the same technology. The simulation results obtained in-term of ENOB and power consumption are satisfactory for the target application.

Analog-to-Digital Converters (ADCs) can be classified into two categories namely Nyquist-rate ADCs and OversampledADCs. Nyquist-rate ADCs can process very high bandwidths while Oversampling ADCs provide high resolution using coarse quantizers and support lower input signal bandwidths. This work describes a Reconfigurable ADC (R-ADC) architecture which models 14 different ADCs utilizing four four-bit flash ADCs and four Reconfigurable Blocks (RBs). Both Nyquist-rate and Oversampled ADCs are included in the reconfiguration scheme. The R-ADC supports first- and second-order Sigma-Delta (ΣΔ) ADCs. Cascaded ΣΔ ADCs which provide high resolution while avoiding the stability issues related to higher order ΣΔ loops are also included. Among the Nyquist-rate ADCs, pipelined and time interleaved ADCs are modeled. A four-bit flash ADC with calibration is used as the basic building block for all ADC configurations. The R-ADC needs to support very high sampling rates (1 GHz to 2 GHz). Hence switched-capacitor (SC) based circuits are used for realizing the loop filters in the ΣΔ ADCs. The pipelined ADCs also utilize an SC based block called Multiplying Digital-to-Analog Converter (MDAC). By analyzing the similarities in structure and function of the loop filter and MDAC, a RB has been designed which can accomplish the function of either block based on the selected configuration. Utilizing the same block for various configurations reduces power and area requirements for the R-ADC. In SC based circuits, the minimum sampling capacitance is limited by the thermal noise that can be tolerated in order to achieve a specific ENOB. The thermal noise in a ΣΔ ADC is subjected to noise shaping. This results in reduced thermal noise levels at the inputs of successive loop filters in cascaded or multi-order ΣΔ ADCs. This property can be used to reduce the sampling capacitance of successive stages in cascaded and multi-order ΣΔ ADCs. In pipelined ADCs, the thermal noise in successive stages are reduced due to the inter-stage gain of the MDAC in each stage. Hence scaling of sampling capacitors can be applied along the pipeline stages. The RB utilizes the scaling of capacitor values afforded by the noise shaping property of ΣΔ loops and the inter-stage gain of stages in pipelined ADCs to reduce the total capacitance requirement for the specified Effective Number Of Bits (ENOB). The critical component of the RB is the operational amplifier (opamp). The speed of operation and ENOB for different configurations are determined by the 3 dB frequency and DC gain of the opamp. In order to find the specifications of the opamp, the errors introduced in ΣΔ and pipelined ADCs by the finite gain and bandwidth of the opamp were modeled in Matlab.The gain and bandwidth requirements for the opamp were derived from the simulation results. Unlike Nyquist-rate ADCs, the ΣΔ ADCs suffer from stability issues when the input exceeds a certain level. The maximum usable input level is determined by the resolution of the quantizer and the order of the loop filter in the ΣΔADC. Using Matlab models, the maximum value of input for different oversampling ADC configurations in the R-ADC were found. The results obtained from simulation are comparable to the theoretical values. The cascaded ADCs require digital filter functions which enable the cancellation of quantization noise from certain stages. These functions were implemented in Matlab. For the R-ADC, these filter functions need to run at very high sampling rates. The ΣΔ loop filter transfer functions were chosen such that their coefficients are powers of two, which would allow them to be implemented as shift and add operations instead of multiplications. The R-ADC configurations were simulated in Matlab. A schematic for the R-ADC was developed in Cadence using ideal switches and a finite gain, single-pole operational transconductance amplifier model. The ADC configuration was selected by four external bits. Performance parameters such as SNR, SNDR and SFDR obtained from simulations in Cadence agree with those from Matlab for all ADC configurations.

The constant strive for improvement of digital video capturing speeds together with power efficiency increase, has lead to tremendous research activities in the image sensor readout field during the past decade. The improvement of lithography and solid-state technologies provide the possibility of manufacturing higher resolution image sensors. A double resolution size-up, leads to a quadruple readout speed requirement, if the same capturing frame rate is to be maintained. The speed requirements of conventional serial readout techniques follow the same curve and are becoming more challenging to design, thus employing parallelism in the readout schemes appears to be inevitable for relaxing the analog readout circuits and keeping the same capturing speeds. This transfer however imposes additional demands to parallel ADC designs, mainly related to achievable accuracy, area and power. In this work a 12-bit Cyclic ADC (CADC) aimed for column-parallel readout implementation in CMOS image sensors is presented. The aim of the conducted study is to cover multiple CADC sub-component architectures and provide an analysis onto the latter to a mid-level of depth. A few various Multiplying DAC (MDAC) structures have been re-examined and a preliminary redundant signed-digit CADC design based on a 1.5-bit modified flip-over MDAC has been conducted. Three comparator architectures have been explored and a dynamic interpolative Sub-ADC is presented. Finally, some weak spots degrading the performance of the carried-out design have been analyzed. As an architectural improvement possibility two MDAC capacitor mismatch error reduction techniques have been presented.

Methane derived authigenic carbonate (MDAC) precipitation occurs within marine sediments as a byproduct of the microbial anaerobic oxidation of methane (AOM). While these carbonates form in chemical and isotopic equilibrium with the fluids from which they precipitate, burial diagenesis and recrystallization can overprint these signals. Plane polarized light (PPL) and cathodoluminescent (CL) petrography have allowed for detailed characterization of carbonate phases and their subsequent alteration. Modern MDACs sampled offshore in northern Cascadia (n =33) are compared with paleoseep carbonates (n =13) uplifted on the Olympic Peninsula in order to elucidate primary vs. secondary signals, with relevance to interpretations of the carbonate record. The modern offshore environment (S. Hydrate Ridge and Barkley Canyon) is dominated by metastable acicular and microcrystalline aragonite and hi-Mg calcite (HMC) that with time will recrystallize to low-Mg calcite (LMC). The diagenetic progression is accompanied by a decrease in Mg/Ca and Sr/Ca ratios while variation in Ba/Ca depends upon the Ba-concentration of fluids that spur recrystallization. CL images discern primary carbonates with high Mn/Ca from secondary phases that reflect the Mn- enrichment that characterizes deep sourced fluids venting at Barkley Canyon. Methane along the Cascadia continental margin is mainly of biogenic origin, where reported strontium isotopic values reflect a mixture of seawater with fluids modified by reactions with the incoming Juan de Fuca plate. In contrast, the Sr-isotopic composition of carbonates and fluids from Integrated Ocean Drilling Program (IODP) Site U1329 and nearby Barkley Canyon point to a distinct endmember (lowest ⁸⁷Sr/⁸⁶Sr = 0.70539). These carbonates also show elevated Mn/Ca and δ¹⁸O values as low as -12‰, consistent with a deep-source of fluids feeding thermogenic hydrocarbons to the Barkley Canyon seeps. Two paleoseep carbonates sampled from the uplifted Pysht/Sooke Fm. have ⁸⁷Sr/⁸⁶Sr values similar to those of the anomalous Site U1329 and Barkley Canyon carbonates (⁸⁷Sr/⁸⁶Sr = 0.70494 and 0.70511). We postulate that the ⁸⁷Sr-depleted carbonates and pore fluids found at Barkley Canyon represent migration by the same type of deep, exotic fluid as is found in high permeability conglomerate layers down to 190 mbsf at Site U1329, and which fed paleoseeps in the Pysht/Sooke Fm. These exotic fluids likely reflect interaction with the 52-57 Ma igneous Crescent Terrane, which is located down-dip from both Barkley Canyon and Site U1329. This previously unidentified endmember fluid in northern Cascadia may have sourced cold seeps in this margin since at least the late Oligocene. / Graduation date: 2012