Daniela De Venuto

Design of an integrated low-noise read-out system for DNA capacitive sensors

This paper presents an electronic system for a fast DNA label-less detection. The sensitivity of the capacitive sensor in use is improved by depositing an insulating self-assembled monolayer (SAM) over the golden electrodes. The capacitance shift due to the hybridization effect is monitored by means of a charge-sensitive amplifier and digitalized by means of a comparator and a counter. The read-out solution demonstrates the ability to identify a 0.01% variation on the capacitive value of the sensor. Results from measurements with the optimized sensor show the reliability of the electronics. The investigated solution is suitable for monolithic systems or for a micro-fabricated array of sensors. An example of the integrated front-end is described and performances and noise evaluation are reported here.

Testing of analogue circuits via (standard) digital gates

The possibility of using window comparators for on-chip (and potentially on-line) response evaluation of analogue circuits is investigated. No additional analogue test inputs are required and the additional circuitry can be realised either by means of standard digital gates taken from an available library or by full custom designed gates to obtain an observation window tailored to the application. With this approach, the test overhead can be kept extremely low. Due to the low gate capacitance also the load on the observed nodes is very low. Simulation results for some examples show that 100% of all assumed layout-realistic faults could be detected.

Designing a Cyber–Physical System for Fall Prevention by Cortico–Muscular Coupling Detection

The authors present wearable noninvasive electronics that prevent a human from falling. It deducts a probable fall from EEG and EMG information and provides a real-time alarm signal for protection.

Low power 12-bit SAR ADC for autonomous wireless sensors network interface

Design strategies for power effective and high resolution Successive-Approximation ADCs for autonomous multi-sensor systems are discussed. Specifically, an optimisation for lowest possible power consumption of comparators is addressed and evaluated using both simulations and measurements of a fabricated Si test-chip. The proposed design solution is capable to provide a 12-bit resolution at 50-kHz with only 0.1uW power consumption on a 1.2-V supply. The achieved Figure-of-Merit is 165 ƒJ/convertion-step is, to our knowledge, the best ever reported. The complete ADC area is 0.35 mm2 in NXP 0.14um CMOS technology with only three metal layers.

Automatic repositioning technique for digital cell based window comparators and implementation within mixed-signal DfT schemes

The possibility of using window comparators for the on-chip evaluation of signals in the analogue circuit part has been demonstrated and is shortly summarized. One of the problems is the lot-to-lot variation of the comparator window. An automatic window repositioning technique is detailed that allows to compensate the window shift. The components for the implementation comprising a reference comparator and the evaluation comparators are described along with the implementation of the technique. It is shown, that this technique allows the automatic lot condition adjustment of the evaluation comparators. Furthermore the technique can provide lot specific information to an automated test equipment that can be documented in the test results due to its diagnosis capability.

Digital Window Comparator DfT Scheme for Mixed-Signal ICs

The possibility of using window comparators for on-chip and potentially also on-line response evaluation of analogue circuits is investigated. No additional analogue test inputs are required. The additional circuitry can be either realised by means of standard digital gates taken from an available library or by full custom designed gates. With only a few gates an observation window can be realized, tailored to the application needs. With this approach, the test overhead can be kept extremely low. Due to the low gate capacitance also the load on the observed nodes is very low. Simulation results for some examples show that 100% of all assumed layout-realistic faults could be detected.

Multiplexing pH and temperature in a molecular biosensor

Robust and reliable measurements in electrochemical biosensing of molecules are crucial for personalized medicine. Electrochemical sensors based on cytochrome P450 can detect the large majority of drugs commonly used in pharmacological treatments. The same cytochrome can detect different substrates; each of them changes the electrochemical response of the enzyme in a specific manner. Our system exploits the measure of electrical potential to identify the drug type, while current measurements decode the drug concentration. Since potential and current are affected by pH and temperature, and since variations occur in the patient samples, we propose a novel design for multiplexing biosensing with pH and temperature control, which ensures more precise measurements for drugs identification and their quantification.

Steps towards the use of silicon drift detectors in heavy ion collisions at LHC

Abstract The inner tracking system of the ALICE detector for PbPb collisions at the LHC require a very good granularity in the innermost planes, due to the high particle density, up to 8000 particles per unit of rapidity. The silicon drift detectors are a very good candidate for this application, but up to now no large system using this technology has been industrially produced and operated in experiments. One of the first steps towards large scale production is the study of the doping uniformity in commercially available Si wafers. The understanding of doping fluctuations is of fundamental importance since they introduce deviations of the electron trajectories from the expected ones. In addition, it is also necessary to know the changes possibly introduced by different processing steps in the resistivity profiles. We report here the results of measurements of resistivity profiles for NTD silicon wafers both before and after processing.

Gait analysis for fall prediction using EMG triggered movement related potentials

Abnormal gait is an usual feature in neurodegenerative disease (i.e.: Huntington Chorea, Parkinson and Alzheimer), while the capability to maintain a stable posture and fluid walking is progressive impaired in aging. Monitoring and correcting the insurgence of abnormal dynamic balance opens new scenarios in the cure of these diseases and falls prevention. In this work, we present a study based on EEG time-frequency analysis to identify the correlation between synchronized EEG and EMG signals for gait analysis. Several tools for gait analysis are developed and experimented i.e. EMG trigger generation with dynamic threshold, EMG co-contraction, EEG movement related potentials (MRPs) and EEG event related desynchronizations (ERDs). This work particularly focus on gait analysis indexes implementation and experimentally obtained results based on a large dataset, including different type of gait i.e. normal gait, perturbed gait and gait during a second cognitive task (DT). A weighted average on the calculated indexes are exploited to quantify the falling risk.

A novel multi-working electrode potentiostat for electrochemical detection of metabolites

A novel single-chip and multiplexed read-out circuit for multi-electrode electrochemical sensors, in standard 0.18 µm UMC CMOS technology, is presented. The circuit is a part of a fully-integrated biochip (in design) for the detection of multiple metabolites. The proposed topology is based on the potentiostat approach, and it is devoted to detect currents within the range of 250 pA – 650 nA for an electrode active area of 0.25 mm2. The need of multi-metabolites monitoring asks for a system with multi-working electrodes. In the proposed configuration, switches select one working electrode at each clock phase, while the others are short-circuited to the reference one, in order to nullify the injected current inside the counter. Low noise and low energy topology (50µW at 1.5V of voltage supply) is employed for the control amplifier. The linearity of the proposed read-out circuit allows accuracy better than 0.1%.