Optimal Geometry of CMOS Voltage-Mode and Current-Mode Vertical Magnetic Hall Sensors

Four different geometries of a vertical Hall sensor are presented and studied in this paper. The current spinning technique compensates for the offset and the sensors, driven in current-mode, provide a differential signal current for a possible capacitive integration over a defined time-slot. The sensors have been fabricated using a 6-metal 0.18-μm CMOS technology and fully experimentally tested. The optimal solution will be further investigated for bendable electronics. Measurement results of the four structures over the 10 available samples show for the best geometry an offset of 41.66 ± 8 μT and a current-mode sensitivity of 9 ± 0.1 %/T. Since the figures widely change with geometry, a proper choice secures optimal performance

Conjuntos líticos en contextos agrarios: el caso del sitio Alto Juan Pablo (departamento Belén, Catamarca)

Tradicionalmente, el estudio del registro lítico no constituyó una parte central en las investigaciones de las sociedades agro-alfareras y menos aún en contextos exclusivamente productivos. En este trabajo consideramos que el análisis de la evidencia lítica en dichos contextos puede contribuir a una mayor comprensión de los modos de habitar los paisajes agrarios prehispánicos. Para ello llevamos adelante análisis tecno–morfológicos como así también de microfósiles presentes como residuos de uso en los materiales líticos recuperados en superficie del sitio Alto Juan Pablo. Éste último, ubicado en el valle de El Bolsón (Departamento Belén, provincia de Catamarca), consiste en un pequeño emplazamiento exclusivamente agrícola (ya que no hemos identificado ninguna estructura residencial asociada), adscripto cronológicamente al Período Formativo. Frente al hecho de que el sitio bajo estudio se trata de un emplazamiento exclusivamente productivo, podemos pensar que el conjunto lítico colectado habría estado asociado a las actividades agrícolas allí llevadas a cabo, más que a las residenciales. A partir de los análisis realizados, podemos proponer algunas de las tareas que podrían haber acompañado la cotidianeidad de las actividades agrícolas, como ser la regularización, mantenimiento o reciclaje de artefactos confeccionados fuera del sitio, como así también hipotetizar posibles funciones para algunas piezas. Finalmente, a través de los resultados del trabajo aquí presentado, observamos que la incorporación de este tipo de materialidad al estudio de los paisajes agrarios prehispánicos puede traducirse en una comprensión más enriquecida de estos últimos.Traditionally, in the context of agricultural societies research, the study of lithic assemblages was scarce, especially in exclusively productive sites. In this paper, we consider that the analysis of lithic evidence in such contexts, contribute to understand the way of dwelling the prehispanic agrarian landscapes. Thereby, we conduct a techno–morphological study, as well as microfossils analysis of the surface lithic assemblages recovered from Alto Juan Pablo, a formative site located in the Bolsón valley (Belén department, Province of Catamarca). The fact that this site is an exclusively productive location, allows us to think that the lithic material collected, may have been associated with the agricultural activities carried out there. From the analysis conducted in this work, we propose that some tasks such as the regularization, maintenance or recycling of artifacts that were not manufactured on site, could accompany the daily agrarian activities at Alto Juan Pablo. Moreover, we also propose some hypotheses about possible functions for those artifacts which functionality did not seem obvious. Through all this, we believe that integrating this type of materiality to the study of prehispanic agrarian landscapes, may lead to a better understanding of these spaces.Fil: Maloberti, Mariana. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Arqueología y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mauri, Eduardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

Capacitor Mismatch Calibration Technique to Improve the SFDR of 14-Bit SAR ADC

This paper presents mismatch calibration technique to improve the SFDR in a 14-bit successive approximation register (SAR) analog-to-digital converter (ADC) for wearable electronics application. Behavioral Monte-Carlo simulations are applied to demonstrate the effect of the proposed method where no complex digital calibration algorithm or auxiliary calibration DAC needed. Simulation results show that with a mismatch error typical of modern technology, the SFDR is enhanced by more than 20 dB with the proposed technique for a 14-bit SAR ADC

High-Resolution ADCs Design in Image Sensors

This paper presents design considerations for high-resolution and high-linearity ADCs for biomedical imaging ap-plications. The work discusses how to improve dynamic spec-ifications such as Spurious Free Dynamic Range (SFDR) and Signal-to-Noise-and-Distortion Ratio (SNDR) in ultra-low power and high-resolution analog-to-digital converters (ADCs) including successive approximation register (SAR) for biomedical imaging application. The results show that with broad range of mismatch error, the SFDR is enhanced by about 10 dB with the proposed performance enhancement technique, which makes it suitable for high resolution image sensors sensing systems

High Linearity SAR ADC for Smart Sensor Applications

This paper presents capacitive array optimization technique to improve the Spurious Free Dynamic Range (SFDR) and Signal-to-Noise-and-Distortion Ratio (SNDR) of Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) for smart sensor application. Monte Carlo simulation results show that capacitive array optimization technique proposed can make the SFDR, SNDR and (Signal-to-Noise Ratio) SNR more concentrated, which means the differences between maximum value and minimum value of SFDR, SNDR and SNR are much smaller than the conventional calibration techniques, more stable performance enhancement can be achieved, and the averaged SFDR is improved from 72.9 dB to 91.1 dB by using the capacitive array optimization method, 18.2 dB improvement of SFDR is obtained with only little expense of digital logic circuits, which makes it good choice for high resolution and high linearity smart sensing systems

A handheld high-sensitivity micro-NMR CMOS platform with B-field stabilization for multi-type biological/chemical assays

We report a micro-nuclear magnetic resonance (NMR) system compatible with multi-type biological/chemical lab-on-a-chip assays. Unified in a handheld scale (dimension: 14 x 6 x 11 cm³, weight: 1.4 kg), the system is capable to detect<100 pM of Enterococcus faecalis derived DNA from a 2.5 μL sample. The key components are a portable magnet (0.46 T, 1.25 kg) for nucleus magnetization, a system PCB for I/O interface, an FPGA for system control, a current driver for trimming the magnetic (B) field, and a silicon chip fabricated in 0.18 μm CMOS. The latter, integrated with a current-mode vertical Hall sensor and a low-noise readout circuit, facilitates closed-loop B-field stabilization (2 mT → 0.15 mT), which otherwise fluctuates with temperature or sample displacement. Together with a dynamic-B-field transceiver with a planar coil for micro-NMR assay and thermal control, the system demonstrates: 1) selective biological target pinpointing; 2) protein state analysis; and 3) solvent-polymer dynamics, suitable for healthcare, food and colloidal applications, respectively. Compared to a commercial NMR-assay product (Bruker mq-20), this platform greatly reduces the sample consumption (120x), hardware volume (175x), and weight (96x)

Disuasión y Castogo desde una Perspectiva Lockeana

This article formulates a deterrence theory of punishment based on Lockean premises. Following authors such as Warren Quinn and Daniel Farrell, it is claimed that a justification for the right to punish must be built upon the recognition of the importance of a right to issue retaliatory threats. Contrary to those authors, however, the articulation of such recognition is made within a Lockean theory of individual rights. This allows us to appreciate the specific role deterrence has in a plausible conception of punishment, and thus address certain objections that have been formulated recently, especially by David Boonin

A 900 MHz, 0.9 V low-power CMOS downconversion mixer

A low-voltage, low-power mixer operating at a supply voltage of 0.9 V while consuming 4.7 mW is presented. The circuit achieves the multiplication using current mode processing. Moreover, non-conventional differential pairs that do not require current tail generators are utilized. The circuit has been fabricated in a standard double-poly, triple-metal 0.35 /spl mu/m CMOS process having a threshold voltage of 0.6 V. Measurement results for 900 MHz and 800 MHz input signals indicate that the circuit has an IIP3 of 3.5 dBm, a 1 dB compression point of -8 dBm and a noise figure of 13.5 dB.peer-reviewe