Readout Circuitry Research Articles

On an Integrated Gas Sensing System Based on an AlGaN/GaN Heterostructure Compound Semiconductor

An interesting integrated gas sensing system, based on an AlGaN/GaN heterostructure compound semiconductor is developed and investigated. This gas detecting system consists of triple gas sensors and a gas sensing readout circuitry. Good gas sensing responses with remarkable current variations of 5.56 mA (@1000 ppm H2/air), 19.06 μA (@1000 ppm NH3/air), and 0.82 mA (@100 ppm NO2/air) are obtained at 200°C, respectively. The corresponding transient states are also demonstrated in this work. From the employed detecting readout system, the gas concentrations of introduced gases (H2, NH3, and NO2) could be appropriately determined and identified. In addition, a novel gray polynomial differential model (GPDM) is employed to effectively reduce redundant gas sensing data and decrease the data transmission load. From experimental results, the studied integrated gas detecting system shows advantages of multiple gas detection capability, easy operation, low cost, and high portability. Therefore, this gas sensing system shows the promise for high-performance multiple gas detecting applications.

Photon-Quantum-Noise-Limited Pixel Architecture in Amorphous-Silicon Technology for Large-Area Digital Imaging Applications

An X-ray photon-quantum-noise-limited voltage-controlled oscillator (VCO)-based pixel architecture in amorphous-silicon (a-Si) technology is reported for large-area digital medical imaging applications. In this research, the X-ray generated input charge on the input capacitor is converted into an oscillating frequency signal output at the pixel level. The VCO pixel is fabricated in-house using a-Si technology, and experimental results are presented. Readout circuitry is proposed which can be optimized to reduce the fixed pattern noise and fringing effects in an imaging array containing many such VCO pixels. The phase noise and stability performance of the single-pixel VCO are measured and analyzed. This architecture has the lowest input referred noise among all reported a-Si pixel architectures and is the first photon-quantum-noise-limited pixel architecture in a-Si technology. The pixel's valid input range is measured to be 120 e- all the way to 5 ×106 e-. This shows that the pixel has a very high dynamic range. The proposed architecture is particularly promising for large-area photon-quantum-noise-limited digital imaging applications (e.g., protein crystallography) due to its small input referred electronic noise, high sensitivity, and ease of fabrication in large-area a-Si technology.

Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

In this paper, we will present a new small pixel CdTe/CZT detector for sub-500μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X–Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2–5mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper.

DVCC based Readout Circuitry for Water Quality Monitoring System

new configuration realizing water quality monitoring device using ISFET involving CMOS differential voltage current conveyor (DVCC) based low pass filter free from trans-conductance variation using Low-voltage PMOS bulk- driven cascade current mirror (P MOS BDCCM) current mirrors is proposed. The circuit uses four DVCCs as active elements and together with two capacitors and five resistors as passive elements, only one current mirror. The use of this active component makes the implementation simple and attractive. The functionality of the circuit is tested using Tanner simulator version 15 for a 70nm CMOS process model also the transfer function realization is done on MATLAB R2011a version, the Very high speed integrated circuit Hardware description language(VHDL) code for the same scheme is simulated on Xilinx ISE 10.1 and various simulation results are obtained. Simulation results are included to demonstrate the results. OTA's. These applications are suffer from low band widths (BW's) arising due to stray and circuit capacitances. Also the need for low voltage, low power circuits makes these circuits not suitable for water quality monitoring as these circuits required the minimum bias voltage depends on the threshold voltage of the MOSFETs. However, with the advancement in the analog VLSI new analog devices are based on currents are developed called current mode circuits (CMC's). These circuits have a significant advantage of low power, low voltages and can operate over wide dynamic range. These circuits, CMC can offer to the designer large bandwidths, greater linearity, wider dynamic range, simple circuitry and low power consumption. Current feedback op-amps (CFOAs), operational floating conveyors (OFCs) and current conveyors (CCs) etc. are popular CMC configuration and most widely used structure among them is DVCC, extension of the second- generation current conveyor (CCII). Hence, we decided to use the DVCC in the proposed scheme.

CMOS high density electrical impedance biosensor array for tumor cell detection

We present a high-throughput label-free electrical-impedance spectroscopy (EIS) platform composed of a 96 × 96 microelectrode array for counting and analysis of breast tumor cells (MCF-7). These Au-electrodes are densely packed within a 3.5 mm × 3.5 mm interrogation region. Each Au-electrode has an edge-length of 25 μm designed to detect single tumor cell by electrical impedance spectroscopy. The detected signal is read out via an integrated circuit (IC) of addressable electrode-selection-switch array manufactured with 0.18 μm CMOS technology. The independently addressable microelectrode array is integrated onto a printed circuit board (PCB) containing associated circuitry for electrode switching and readout. MCF-7 cells were dispensed onto the chip surface and EIS measurements were recorded before and after the cell dispensation. On an average 20% increase in impedance was found associated with cell occupancy on the electrode surface. A positive correlation was observed between cell detection with optical microscopy and with electrical scanning.

High-resolution real-time ion-camera system using a CMOS-based chemical sensor array for proton imaging

Abstract We describe a complete lab-on-a-chip type ion-sensitive chemical sensor array system for imaging proton concentration and flow. The core of the imaging system relies on a 715.8 μm × 715.8 μm large 64 × 64-pixel ISFET sensor array that is designed and fabricated in a conventional 4-metal 0.35 μm CMOS process along with readout circuitry and additional electronics. The high-speed and real-time data acquisition of ∼100 frame per second (fps), 40 μs per pixel, results in a large amount of data that is streamed to the hard disk. Image reconstruction methods allow visualization of the dynamic behavior of chemical substances and ionic spreads over the sensor array at a resolution of the size of a pixel. The functionalities of the on-chip ion-camera device are demonstrated using appropriate acid and alkaline solutions. A pH sensitivity of 20 mV/pH was achieved without modification to the foundry processed chip.

A ${\rm Z}$-Axis Quartz Tuning Fork Micromachined Gyroscope Based on Shear Stress Detection

This paper proposes a novel quartz micromachined gyroscope. The structure is designed by using shear stress detection method which can simplify the sidewall electrodes obviously. Furthermore, a tuning fork is introduced by the structure to obtain better differential vibrations. In order to increase the sensitivity of the sensor, the sense beam is designed to be a symmetric tapered beam. The device was fabricated using quartz anisotropic wet etching process. The drive mode frequency is 14.99 kHz, and the quality factor is 7600 in air. The sense mode frequency is 14.25 kHz, and the quality factor is 600 in air. Therefore, this gyroscope can operate at atmosphere pressure properly. The sensor is tested on a rate table through a specially designed readout circuitry. The sensitivity is 23.9 and the nonlinearity is 1.1% in range of . The noise floor is 0.1 .

Development of a Low Cost Device for Measuring Solar Irradiance

For a determination of the system’s efficiency and decrease the cost, a low cost system for measuring solar irradiance is designed. By analyzing the influence of solar irradiance and temperature to solar cell, we have found that in case of different temperatures the variation of short-circuit current (Isc) in function of solar irradiation incident (E) is always linear. Then the read-out circuitry is designed to measure and convert the signal which is detected by the photoelectric cell and thermocouples. At last, the software is developed to compensate the temperature and make sure the device work normally. The results of detecting the system show that it’s effective and reliable.

Integration of field effect transistor-based biosensors with a digital microfluidic device for a lab-on-a-chip application

A new platform for lab-on-a-chip system is suggested that utilizes a biosensor array embedded in a digital microfluidic device. With field effect transistor (FET)-based biosensors embedded in the middle of droplet-driving electrodes, the proposed digital microfluidic device can electrically detect avian influenza antibody (anti-AI) in real time by tracing the drain current of the FET-based biosensor without a labeling process. Digitized transport of a target droplet enclosing anti-AI from an inlet to the embedded sensor is enabled by the actuation of electrowetting-on-dielectrics (EWOD). A reduction of the drain current is observed when the target droplet is merged with a pre-existing droplet on the embedded sensor. This reduction of the drain current is attributed to the specific binding of the antigen and the antibody of the AI. The proposed hybrid device consisting of the FET-based sensor and an EWOD device, built on a coplanar substrate by monolithic integration, is fully compatible with current fabrication technology for control and read-out circuitry. Such a completely electrical manner of inducing the transport of bio-molecules, the detection of bio-molecules, the recording of signals, signal processing, and the data transmission process does not require a pump, a fluidic channel, or a bulky transducer. Thus, the proposed platform can contribute to the construction of an all-in-one chip.

Development of a Low Cost Device for Measuring Solar Irradiance

For a determination of the system’s efficiency and decrease the cost, a low cost system for measuring solar irradiance is designed. By analyzing the influence of solar irradiance and temperature to solar cell, we have found that in case of different temperatures the variation of short-circuit current (Isc) in function of solar irradiation incident (E) is always linear. Then the read-out circuitry is designed to measure and convert the signal which is detected by the photoelectric cell and thermocouples. At last, the software is developed to compensate the temperature and make sure the device work normally. The results of detecting the system show that it’s effective and reliable.

A 3-$\mu\hbox{W}$ CMOS Glucose Sensor for Wireless Contact-Lens Tear Glucose Monitoring

This paper presents a noninvasive wireless sensor platform for continuous health monitoring. The sensor system integrates a loop antenna, wireless sensor interface chip, and glucose sensor on a polymer substrate. The IC consists of power management, readout circuitry, wireless communication interface, LED driver, and energy storage capacitors in a 0.36-mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> CMOS chip with no external components. The sensitivity of our glucose sensor is 0.18 μA·mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ·mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . The system is wirelessly powered and achieves a measured glucose range of 0.05-1 mM with a sensitivity of 400 Hz/mM while consuming 3 μW from a regulated 1.2-V supply.

Low temperature amorphous growth of semiconducting Y–Ba–Cu–O oxide thin films in view of infrared bolometric detection

YBa2Cu3O6+x (YBCO) compounds are well known to exhibit superconducting properties for x>0.5 and semiconducting properties for lower oxygen content. In this work, YBCO oxide thin films of the semiconducting phase were deposited by direct-current (DC) hollow cathode sputtering at low temperature in the 100 to 400°C range. Structural, electrical and optical properties are investigated and discussed in relation with the envisaged bolometric detection application. Structural characterizations show that films are amorphous, with a granular structure of low roughness (3nm rms). DC electrical measurements both reveal that films grown at 100°C exhibit a high temperature coefficient of resistance (TCR~−3%K−1 to −4%K−1 at 300K) and an optimized low resistivity value of 345Ω·cm at 300K. Consequently, this material is suitable for uncooled infrared bolometer application and can be deposited at 100°C in a complementary metal-oxide-semiconductor compatible technological process for co-integration with readout circuitry. In addition, optical measurements performed in the 0.5 to 2.2μm wavelength range on films grown at 100°C highlight optical conductivity values in line with those expected for YBCO material, as well as the presence of two optical band gaps that are discussed with respect to the film nanostructure.

First Performance Evaluation of an X-Ray SOI Pixel Sensor for Imaging Spectroscopy and Intra-Pixel Trigger

We have been developing a monolithic active pixel sensor with the 0.2 μm Silicon-On-Insulator (SOI) CMOS technology, called SOIPIX, for the wide-band X-ray imaging spectroscopy on future astronomical satellites. SOIPIX includes a thin CMOS-readout-array layer and a thick high-resistivity Si-sensor layer stacked vertically on a single chip. This arrangement allows for fast and intelligent readout circuitries on-chip, providing advantages over the charge-coupled device (CCD). We have designed and built a new SOIPIX prototype XRPIX1 for X-ray detection. XRPIX1 implements a correlated double sampling (CDS) readout circuit in each pixel to suppress the reset noise. We obtained an energy resolution of full width at half maximum of 1.2 keV (5.4%) at 22 keV with a chip having a 147 μm sensor depletion at a back bias of 100 V cooled to -50°C. Moreover, XRPIX1 offers intra-pixel hit trigger (timing) and two-dimensional hit-pattern (position) outputs. We also confirmed the trigger capability by irradiating a single pixel with laser light.

A tactile sensing array with tunable sensing ranges using liquid crystal and carbon nanotubes composites

This work presents the development of a novel 4×4 pressure sensing array with tunable sensing ranges. Carbon nanotubes (CNTs) dispersed in nematic liquid crystals (LC) composite is employed as the resistive sensing material. The structure of the sensing element, in which the LC–CNT composite is sealed, consists of a deformable PDMS elastomeric structure, an indium tin oxide (ITO) glass substrate and an ITO PET film. The force sensing ranges can be tuned by varying frequency of the driving voltage supplied by the array scanning circuitry. This tunable capability can be employed for the applications which require different measurement ranges of forces, without the need of adjusting the dynamic ranges of the sensor readout circuitry. The characteristics of the devices are measured and the pressure images with tunable capability are successfully captured. The driving and scanning circuit for resistive sensing array is also designed and implemented.

Microsystem Technologies: foreword to special issue on design, test, integration and packaging of MEMS/MOEMS, 2010

The symposium on design, test, integration and packaging of MEMS/MOEMS (DTIP) was held in Seville, Spain, 5–7 May 2010, as a follow up to previous issues held in 1999 and 2000 in Paris, France, in 2001, 2002, 2003 in Mandelieu-La Napoule, France, in 2004 and 2005 in Montreux, Switzerland, and in 2006, 2007 in Stresa, Italy, in 2008 in Nice, France and in 2009 in Rome, Italy. This series of symposia is a unique single-meeting event expressly planned to bring together participants interested in manufacturing microstructures and participants interested in design tools to facilitate the conception of these microstructures. The symposium is traditionally composed of two conferences running in parallel: one on CAD, design and test (CDT), and another one on microfabrication, integration and packaging (MIP). In addition, participants of both conferences can attend invited talks and special sessions. This special issue is collecting reviewed and unabridged versions of papers presented at the symposium. The papers have been again refereed, along the usual refereeing process in force at Microsystem Technologies. We are proud to offer these papers to the readers of this journal now. From 37 revised papers submitted to this special issue, 28 papers have been finally selected. They cover a broad range of topics. They appear in the Special Issue in the following order. A first large collection of ten papers on design, modeling and simulation of devices and components, five papers on embossing and mould, five papers on sensors and read-out circuitry, four papers on packaging and finally two papers on fabrication and two on measurement. We hope that you enjoy these contributions as much as we did.

Research on a Novel Capacitive Pressure Sensor to Measure Chamber Pressures of Different Caliber Artilleries

The research and development on a novel capacitive pressure sensor with an elastic pressure-sensitive element are presented in this paper. As a coaxial cylinder capacitor converter, it uses a circuit cylinder as its stationary anode and the piezo gauge's shell as its moveable cathode with the electrode distance of 0.5 mm. The device's principle and structure are given, and its mechanical characteristics are theoretically simulated by using the finite element software ANSYS. The read-out circuitry was developed. Various physical properties were experimentally tested. Results show that its capacitance is approximately linear to the subjected pressure. Its sensitivity is 0.0099 pF/Mpa, pressure measuring rang is 0-600 Mpa, By using the sensor's shell as its elastic sensitive element, its volume is reduced and its applications are increased, thus it can be used to measure the chamber pressures of various different caliber guns. In addition, its lower cost is helpful to promoting its applications.

A CMOS Image Sensor With On-Chip Image Compression Based on Predictive Boundary Adaptation and Memoryless QTD Algorithm

This paper presents the architecture, algorithm, and VLSI hardware of image acquisition, storage, and compression on a single-chip CMOS image sensor. The image array is based on time domain digital pixel sensor technology equipped with nondestructive storage capability using 8-bit Static-RAM device embedded at the pixel level. The pixel-level memory is used to store the uncompressed illumination data during the integration mode as well as the compressed illumination data obtained after the compression stage. An adaptive quantization scheme based on fast boundary adaptation rule (FBAR) and differential pulse code modulation (DPCM) procedure followed by an online, least storage quadrant tree decomposition (QTD) processing is proposed enabling a robust and compact image compression processor. A prototype chip including 64×64 pixels, read-out and control circuitry as well as an on-chip compression processor was implemented in 0.35 μm CMOS technology with a silicon area of 3.2×3.0 mm2 and an overall power of 17 mW. Simulation and measurements results show compression figures corresponding to 0.6-1 bit-per-pixel (BPP), while maintaining reasonable peak signal-to-noise ratio levels.

Fast Tunable Coupler for Superconducting Qubits

A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.

Development of a Point-of-Care Testing Platform With a Nanogap-Embedded Separated Double-Gate Field Effect Transistor Array and Its Readout System for Detection of Avian Influenza

Label-free electrical detection of avian influenza (AI) is demonstrated for the development of a point-of-care testing (POCT) platform. For a new POCT platform, a novel field effect transistor (FET)-based biosensor array was fabricated with conventional complementary metal-oxide-semiconductor (CMOS) technology. Nanogap-embedded separated double-gate FETs (nanogap-DGFETs) were realized in a 6 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex> </formula> 6 array as a biosensor cartridge. Moreover, the low-noise readout circuit was designed and fabricated using a 0.35- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\mu$</tex></formula> m standard CMOS process. The AI antigen and antibody were bound with the aid of silica-binding proteins (SBP) in the nanogap of the biosensor device. Because the gate dielectric constant was increased by the immobilized biomolecules, the threshold voltage of the nanogap-DGFET was reduced while the drain-to-source current was enhanced. Drain-to-source currents of the nanogap-DGFET array were successfully acquired using the fabricated readout circuitry and measurement setup. This platform is suitable for a simple and effective label-free detection of AI in POCT applications.

A Fully Integrated CMOS Accelerometer Using Bondwire Inertial Sensing

This paper presents the design, implementation, and characterization of a fully integrated accelerometer using a bondwire inertial sensor. The accelerometer was implemented in a standard CMOS process without microelectromechanical processing. The system consists of a gold and aluminum bondwire inertial sensor and readout circuitry. Finite-element analysis was used to characterize the mechanical performance of the accelerometer and reinforce empirical data. The system includes a fully differential frequency modulation downconversion architecture and consumes 13.5 mW while achieving a gain of 10 kHz/g, a bandwidth of 700 Hz, and a resolution of 80 mg. The chip was fabricated in an 0.13-m CMOS process with an area of 1.1 mm.