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Circuit Design (circuit + design)
Selected AbstractsSoft Transfer Printing of Chemically Converted GrapheneADVANCED MATERIALS, Issue 20 2009Matthew J. Allen A transfer printing process that allows precise patterning of chemically converted graphene is reported. The use of a polydimethylsiloxane (PDMS) stamp and surface energy manipulation resulted in successfully transferring spin-coated materials from one substrate to another. The method is capable of transferring sharp features to precise locations. This represents large-scale, high-throughput transfer printing of chemically converted graphene and paves the way for future complementary circuit design. [source] Analog circuit design by nonconvex polynomial optimization: Two design examplesINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2010Siu-Hong Lui Abstract We present a framework for synthesizing low-power analog circuits through global optimization over generally nonconvex multivariate polynomial objective function and constraints. Specifically, a nonconvex optimization problem is formed, which is then efficiently solved through convex programming techniques based on linear matrix inequality (LMI) relaxation. The framework allows both polynomial inequality and equality constraints, thereby facilitating more accurate device modelings and parameter tuning. Compared to traditional nonlinear programming (NLP), the proposed methodology exhibits superior computational efficiency, and guarantees convergence to a globally optimal solution. As in other physical design tasks, circuit knowledge and insight are critical for initial problem formulation, while the nonconvex optimization machinery provides a versatile tool and systematic way to locate the optimal parameters meeting design specifications. Two circuit design examples are given, namely, a nested transconductance(Gm),capacitance compensation (NGCC) amplifier and a delta,sigma (,,) analog-to-digital converter (ADC), both of them being the key components in many electronic systems. Copyright © 2008 John Wiley & Sons, Ltd. [source] A method for acceptability region representation in analogue linear networksINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 10 2009Francesco Grasso Abstract A new simple approach to acceptability region representation in analogue linear circuit design is presented. The proposed method is also able to characterize non-convex and disjoint acceptability regions with low computational effort. In fact, the developed procedure is based on the use of symbolic analysis techniques, which permit one to perform only one simulation of the circuit under consideration, thus reducing the computational efforts. The theoretical basis and the algorithm implementing the technique are presented. A circuital example is also included. Copyright © 2008 John Wiley & Sons, Ltd. [source] New RF extrinsic resistances extraction procedure for deep-submicron MOS transistorsINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 2 2010J. C. Tinoco Abstract The modeling of MOS transistors used for RF applications needs the definition of a lumped equivalent circuit where the intrinsic device and series extrinsic resistances are properly evaluated. The model accuracy depends on the extraction precision of each intrinsic lumped element. In order to determine the intrinsic device behavior, it is necessary to first remove the series extrinsic resistances. For this reason their extraction becomes critical for the modeling of MOS transistors in RF circuit design. Several extraction methods have been proposed; nevertheless, the measurement noise strongly affects the obtained results. The method proposed by Bracale and co-workers is the most robust extraction procedure against measurement noise, but fails to predict correctly the series extrinsic resistances for deep-submicron devices. For those reasons, we deeply analyze the method proposed by Bracale in order to understand and then overcome its limitations. Based on those analyses, a robust extraction method for deep-submicron devices is proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source] A CMOS differential fifth-derivative Gaussian pulse generator for UWB applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Jin He Abstract A CMOS differential fifth-derivative Gaussian pulse generator is presented for Ultrawideband (UWB) applications. The design exhibits low-power consumption, low-circuit complexity, and precise pulse shape to inherently comply with the FCC spectrum mask for indoor UWB applications without the need for a filter. The proposed differential pulse generator was implemented with a 1.8-V, 0.18-,m CMOS process, but only the positive fifth-derivative Gaussian pulse was measured owing to the limitation of the available testing facilities. The measured pulse has peak-to-peak amplitude of 154 mV and a pulse width of 820 ps. Small core area of the differential pulse generator is only 0.028 mm2 because of its all digital circuit design. The average power dissipation is 1.2 mW with a pulse repetition frequency (PRF) of 50 MHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1849,1852, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25342 [source] Integrated the inductors on ultra-thin Si substrate to improve the RF performance for low-noise amplifier applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2010H. L. Kao Abstract This article presents the Q-factor improvement as high as 31% of 0.8 nH spiral inductors of 90-,m-thick silicon substrate on plastic. The improvement of Q-factor is due to reducing the parasitic effect from Si substrate. The loss mechanisms of parasitic effect of inductor have been studied by thinned down the Si substrate to 90 ,m and transfer to plastic. The inductance of the inductors before and after thinned down to 90 ,m Si substrates mounted on plastic are almost identical for radio frequency circuit design. A low 0.2 dB minimum noise figure (NFmin) of low-noise amplifier circuit with 90 ,m Si substrate on plastic was obtained due to the improvement of high Q-factor inductors in the first stage for radio frequency identification applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1576,1579, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25249 [source] Using finite element method to calculate capacitance, inductance, characteristic impedance of open microstrip linesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008Sarhan M. Musa Abstract Microstrip transmission lines have received more interest and attention in microwave integrated circuit design. Analysis and electrical characterization of single and coupled microstrip lines have been a major focus for researchers in integrated circuit technology. In this article, we will illustrate modeling of the capacitance, inductance, and characteristic impedance of quasi-TEM for open microstrip lines using finite element method with COMSOL multiphysics package. In this work, we determine the capacitance per unit length, inductance per unit length, and characteristic impedance of open microstrip lines (single-strip, double strip, and three-strip). We compare our results with those obtained by other methods and found them to be in agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 611,614, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23164 [source] High-frequency scalable compact modelling of Si RF-CMOS technologyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008Antonios Bazigos Abstract The aggressive downscaling of CMOS technologies offers record transit frequencies well above 100 GHz. Efficient RF circuit design, employing such technologies, demands non-linear, scalable compact models with high accuracy up to high frequencies. EKV3 is an advanced MOSFET model, based on charge sheet theory, that meets such demands. Within this paper, the model is validated against DC and RF measurements up to 30 GHz, for various devices of a modern 180 nm CMOS technology. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Design of electronic systems based on functional capabilityQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 1 2008James M. Gilbert Abstract An important measure of design quality is the extent to which a circuit design is able to meets its specification in the presence of component parameter variations. Of equal importance is knowing how to improve this capability most effectively. This paper presents an analysis technique and visualization method which give the designer information about design quality and possible routes to improved quality. The paper introduces two new measures of functional capability, based on the process capability measure Cpk, and shows how these may be linked to the statistical variations in individual component parameters. It then shows how this information may be used to assess the effectiveness of altering the nominal value and variability in each of the component parameters in order to improve circuit performance capability. The analysis required is straightforward and the information is presented in a clear manner which can readily be interpreted by the designer. The effectiveness of the technique has been evaluated through analysis of a number of printed circuit board level analogue and mixed signal circuits and the results of a case study are shown. Copyright © 2007 John Wiley & Sons, Ltd. [source] An over-current protection module for telephone network line cards,an analysis of electro-thermal propertiesQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2002Marina Santo Zarnik Abstract In this paper the results of a finite-element analysis of the electro-thermal behaviour of an over-current protection thick-film hybrid module are presented. The module was designed for protecting the line card of a telephone network against an abnormal surge of current, resulting from accidental shorts between adjacent power feed lines. The switching time of the device is crucial to its effectiveness as a protective element. A transient finite-element thermal analysis was performed in order to predict the dynamic temperature states at the critical points of the circuit design and to evaluate the influence on the switching characteristics. A comparison between simulated and practical results is given. Copyright © 2002 John Wiley & Sons, Ltd. [source] Digital photography: A primer for pathologistsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2004Roger S. Riley Abstract The computer and the digital camera provide a unique means for improving hematology education, research, and patient service. High quality photographic images of gross specimens can be rapidly and conveniently acquired with a high-resolution digital camera, and specialized digital cameras have been developed for photomicroscopy. Digital cameras utilize charge-coupled devices (CCD) or Complementary Metal Oxide Semiconductor (CMOS) image sensors to measure light energy and additional circuitry to convert the measured information into a digital signal. Since digital cameras do not utilize photographic film, images are immediately available for incorporation into web sites or digital publications, printing, transfer to other individuals by email, or other applications. Several excellent digital still cameras are now available for less than $2,500 that capture high quality images comprised of more than 6 megapixels. These images are essentially indistinguishable from conventional film images when viewed on a quality color monitor or printed on a quality color or black and white printer at sizes up to 11×14 inches. Several recent dedicated digital photomicroscopy cameras provide an ultrahigh quality image output of more than 12 megapixels and have low noise circuit designs permitting the direct capture of darkfield and fluorescence images. There are many applications of digital images of pathologic specimens. Since pathology is a visual science, the inclusion of quality digital images into lectures, teaching handouts, and electronic documents is essential. A few institutions have gone beyond the basic application of digital images to developing large electronic hematology atlases, animated, audio-enhanced learning experiences, multidisciplinary Internet conferences, and other innovative applications. Digital images of single microscopic fields (single frame images) are the most widely utilized in hematology education at this time, but single images of many adjacent microscopic fields can be stitched together to prepare "zoomable" panoramas that encompass a large part of a microscope slide and closely simulate observation through a real microscope. With further advances in computer speed and Internet streaming technology, the virtual microscope could easily replace the real microscope in pathology education. Later in this decade, interactive immersive computer experiences may completely revolutionize hematology education and make the conventional lecture and laboratory format obsolete. Patient care is enhanced by the transmission of digital images to other individuals for consultation and education, and by the inclusion of these images in patient care documents. In research laboratories, digital cameras are widely used to document experimental results and to obtain experimental data. J. Clin. Lab. Anal. 18:91,128, 2004. © 2004 Wiley-Liss, Inc. [source] | ||||||||||