By Topic

Circuits, Devices and Systems, IEE Proceedings G

Issue 1 • Date Feb 1991

Filter Results

Displaying Results 1 - 25 of 26
  • Physics-based large-signal heterojunction bipolar transistor model for circuit simulation

    Publication Year: 1991 , Page(s): 97 - 103
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    A comprehensive single heterojunction bipolar transistor (HBT) model suited for circuit simulation is presented. The model is developed in the Gummel-Poon homojunction bipolar transistor model tradition, but adds important heterostructure device physics as well as physical properties of three or four compound materials such as AlGaAs and GaAs. In contrast to the existing HBT models, which use the Gummel-Poon model and fit HBT experimental data by optimising a large pool of parameters extracted from HBT measurements, the present physics-based model requires only the knowledge of the device make-up (such as the doping concentration and layer thickness) and the material parameters (such as the energy bandgap and electron affinity). Comparisons between the model and measured dependencies for AlGaAs-GaAs-GaAs HBTs on important device specifications such as the DC current/voltage characteristics, DC current gain, and cutoff frequency are included View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Alternative control strategies for rule-based transistor placement in CMOS VLSI design

    Publication Year: 1991 , Page(s): 137 - 144
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    A CMOS leaf cell may be regarded as a grid of elements, each of which is a p-type or n-type transistor. An arbitrary placement may be improved by swapping particular transistor pairs. Nine rules have been devised, each of which proposes candidate pairs to be swapped. The number of possible swaps for a given leaf cell is large and a complete exploration of the search space is not computationally feasible. The authors consider the effectiveness of four possible iterative algorithms for the selection of transistor swaps proposed by the rule set and compare them with an algorithm for constructive placement View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noise measure for optimum broadband design

    Publication Year: 1991 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    The definition of noise measure (NM) has been used as a figure of merit, and a circuit has been designed for optimum performance. The circuit possesses maximum gain and minimum noise figure over the design frequency band. Furthermore, to keep the response flat in the frequency range of interest, input and output matching networks have been designed using a Smith chart. The noise measure obtained for the device is 0.45 View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single shunt fault diagnosis in ladder structures with a new series of numbers

    Publication Year: 1991 , Page(s): 38 - 44
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    Diagnosis of a single shunt fault in a ladder structure, by means of conventional input/output ports only and by making measurements at a single test frequency, is presented. Three sets of measurements, namely, forward attenuation, backward attenuation and a specific backward attenuation with an additional series arm impedance, with their corresponding phase-shifts for a sinusoidal input of a particular frequency, are found sufficient to diagnose a fault. The attenuations are expressed in terms of a set of polynomials defined by Morgan-Voyce (1959). The sum of forward and backward attenuation, as well as the difference between forward and the specific backward attenuation, in association with their corresponding phaseshifts, allow the authors to locate and identify faults. A proposition has been made to remove the ambiguities encountered in fault isolation towards the middle of the ladder structure View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Threshold voltage and subthreshold slope of the volume-inversion MOS transistor

    Publication Year: 1991 , Page(s): 133 - 136
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    One dimensional numerical simulations of a silicon on insulator transistor, operated in the volume inversion mode, are presented. It is found that, in the case of thin silicon films, the constant potential approximation holds which allows one to establish analytical expressions for the threshold voltage and subthreshold slope. The very thick film situation is also examined so as to cover the whole range of film thickness View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of recombination current on current gain of HBTs

    Publication Year: 1991 , Page(s): 115 - 119
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    In order to predict more accurately the current gain behaviour of HBTs at low collector current region, surface recombination and interface recombination have to be considered. Recombination current has been obtained by the combination of bulk recombination in the neutral base, interface recombination at the heterointerface, space charge recombination, and surface recombination components. Results from the present model have been compared with experimental results, and the most recent analytical models for abrupt and graded heterojunction bipolar transistors (HBTs). The authors' study shows that this model can predict the device gain more accurately View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Relationship of singular value stability robustness bounds to spectral radius for discrete systems with application to digital filters

    Publication Year: 1991 , Page(s): 5 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    Presents additional results and an application for recently obtained stability robustness bounds on linear time-varying perturbations of an asymptotically stable linear time-invariant discrete-time system. The bounds were developed using Lyapunov theory and singular value decomposition, and provide sufficient conditions for maintaining asymptotic stability for both unstructured and structured perturbations in the state-space discrete system model. A derivation is presented for the relationship between the unstructured perturbation bound and the spectral radius of the system model matrix, showing that the normal form realisation of the system gives the largest unstructured perturbation bound. Both the unstructured and structured perturbation bounds are applied to a recursive digital filter and to coefficient truncation as time-invariant examples to illustrate the use of these relations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance of transfer resistance amplifiers with capacitive sources in optical applications

    Publication Year: 1991 , Page(s): 45 - 51
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    Transfer resistance amplifiers using standard operational amplifiers are often employed when moderate bandwidths and low noise are required from capacitive current sources, such as photodetectors for optical imaging and the samples which are used in the OBIC and EBIC techniques of semiconductor microscopy. Analytic design equations are derived that predict bandwidth and noise performance as a function of source capacitance and allow the selection of the most suitable amplifier for specified conditions. Both the noise performance and frequency response change if the source capacitance departs from its design value, as it does when the reverse bias on a photodiode is altered, and the significance of these changes is calculated. Results from specific design examples, based on standard low-noise operational amplifiers, are discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New approach to automatic symbolic analysis of electric circuits

    Publication Year: 1991 , Page(s): 22 - 28
    Cited by:  Papers (19)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    A new approach to the problem of computer generation of symbolic network functions is presented. The method is based on the application of artificial intelligence techniques and, in particular, on symbolic algebraic manipulation. The computer programs developed by following this approach are presented. An application example is given to illustrate the features and potentials of such programs View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Trap-related effects in AlGaAs/GaAs HEMTs

    Publication Year: 1991 , Page(s): 104 - 108
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    Some AlGaAs/GaAs HEMTs display output resistance and transconductance frequency dispersions that are strongly dependent on the applied drain bias VDS. These frequency and bias dependences have been observed in devices showing a `kink' effect in the DC current/voltage characteristics. All such phenomena appear to be closely correlated and, because of the presence of deep levels in the AlGaAs layer, may be correlated to DX centres. Electron trapping and detrapping times, which, at low VDS, are about 3 and 10 μs, respectively, can be reduced by almost one order of magnitude by an increase in the drain voltage. Consequently, the related frequency-dependent phenomena disappear at frequencies higher than few megahertz View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Minimal-order polynomial satisfying the equality cT p(A)=0

    Publication Year: 1991 , Page(s): 129 - 132
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    In the paper, a space P(c,A) of polynomials satisfying the equality cTp(A)=0 is considered and characterised in detail. As an application, the problem of finding the minimal-order input/output relationship for a discrete-time system x (m+1)=Ax(m)+Bu(m), y(m)=cTx(m)+d( m) is then related to the problem of identification of the minimal-order polynomial of P(c,A) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Numerical procedure for simulating the large-signal quantum behaviour of superconducting tunnel-junction circuits

    Publication Year: 1991 , Page(s): 70 - 76
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    The authors describe a numerical procedure for simulating, in the frequency domain, the large-signal quantum behaviour of superconducting tunnel-junction circuits. It is shown that the steady-state dynamics of a circuit can be decomposed by using the method of harmonic balance, and that the resulting system of coupled nonlinear algebraic equations can be solved through the harmonic Newton method. The presentation is generalised in a number of ways: first, the scheme is described in terms of a generic circuit comprising a tunnel junction and a Thevenin voltage source; secondly, the circuit equations are normalised to the gap voltage and the gap current of the tunnel barrier; and thirdly, an imperfect junction is modelled by convolving an ideal BCS current/voltage characteristic with a Gaussian function View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of a systolic macrocell-based VLSI design style to the design of a single-chip high-performance FIR filter

    Publication Year: 1991 , Page(s): 17 - 21
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    Presents the application of a VLSI design style based on systolic macrocells in the realisation of a single-chip high-performance digital FIR filter. The systolic macrocell design style is well suited for the design of high-performance integrated circuits to be used in digital signal processing. The style uses as design primitives bit-level systolic macrocells designed according to logical and electrical rules that guarantee the required performance. The filter was designed with a 1.5 μm CMOS technology; it occupies an area of 3.74×3.42 mm2 and has 128 coefficients. The expected clock frequency is of about 100 MHz and allows a throughput of the order of 1 million samples per second. The technique applied to the design of the most critical part of the circuit (the clock generation and distribution network) is also described View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-frequency link parallel resonant convertor with fourth-order commutation network

    Publication Year: 1991 , Page(s): 34 - 37
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    A technique of steady-state analysis for the fourth-order parallel resonant convertor circuit is proposed. The method makes use of the two-dimensional state-plane diagram that has been used successfully to analyse resonant convertors of lower order. Theoretical results are verified by computer simulations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Field impoverishment modes in a diode with an AlxGa1-xAs/GaAs heterojunction: a simulation analysis

    Publication Year: 1991 , Page(s): 91 - 96
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    The authors have examined previously the possibility of the formation of low-field domains as opposed to the traditional high-field domains found in Gunn diodes. Initial electron distributions that may lead to the growth of these domains are now further examined by numerical simulation with the purpose of finding conditions that are easier to meet in practice. It is confirmed that a significant number of electrons in the upper valleys is a necessary condition. However, it is found that the charge neutrality, uniform distribution in physical space, and direction of the wave number that were imposed in the previous simulation are not determinant. A AlxGa1-xAs(n)/GaAs(n) abrupt heterojunction is studied next in the frame of the Boltzmann transport equation. It is predicted that it may be used as an electron launcher into upper valleys for impoverishment field domains, provided the composition makes the ternary compound an indirect band gap semiconductor. When the injection guarantees 50% of the electrons in the satellite valleys at the heterojunction plane, the authors' results show that, at a distance of 0.25 μm from the heterojunction interface, as much as 30% of the total number of electrons remains in the upper valleys. A diode that exhibits the formation of repetitive transit time field impoverishment modes is proposed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Second-order switched capacitor building block and its application to the design of silicon efficient filters

    Publication Year: 1991 , Page(s): 9 - 16
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    Two types of 2nd-order switched capacitor (SC) building block are developed to facilitate the design of silicon efficient SC filters. The derivation of their z-domain equivalent admittances, based on the principle of charge conservation, is given. A 2nd-order bandpass filter and a 3rd-order Chebyshev lowpass filter using such building blocks have been successfully implemented with discrete components. In addition to a reduced number of operational amplifiers (OA), a reduction in total capacitance and the number of switches is also achieved. Experimental results are in good agreement with theory View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluation of the impulse response energy of a 2-D linear discrete separable-denominator system

    Publication Year: 1991 , Page(s): 125 - 128
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    A recursive algorithm is presented for parametrically evaluating the impulse response energy of a class of two-dimensional (2-D) linear discrete systems characterised by a proper separable-denominator transfer function. It is useful in connection with current work on a 2-D separable-denominator system (SDS) and its model reduction. The algorithm is illustrated by an example View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Harmonic and intermodulation performance of analogue CMOS circuits owing to mobility reduction

    Publication Year: 1991 , Page(s): 65 - 69
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    The current-voltage characteristic of a MOSFET operating in the saturation region and including the effect of surface-channel mobility reduction is modelled by a third-order polynomial expression. Using this expression, a general expression is obtained for the harmonics and intermodulation performance of a MOSFET operating in saturation and excited by a multi-sinusoidal gate-to-source voltage. Using this expression, the second-harmonic and the third-harmonic distortion performance of a linear voltage-to-current convertor proposed recently has been calculated. The results obtained are compared with previously published results View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Use of inductive compensation for improving bandwidth and noise performance of high frequency optical receiver preamplifiers

    Publication Year: 1991 , Page(s): 52 - 55
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    In the standard bipolar receiver amplifier configuration of a cascode stage followed by an emitter follower, inclusion of an inductor in series with the collector resistor is shown to give an improvement in the noise and bandwidth performance over that of the unmodified circuit. The bandwidth improvement is of the order of a factor of two. The predictions are confirmed by step response measurements View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Nonlinear distortion of an FM signal by a passive network

    Publication Year: 1991 , Page(s): 61 - 64
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    A new technique for prediction of the distortion resulting from the passage of an FM signal into a passive filter is presented. The technique is mathematically simple and closed-form expressions are obtained for the resulting distortion products View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of efficient second and higher degree FIR digital differentiators for midband frequencies

    Publication Year: 1991 , Page(s): 29 - 33
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    Efficient designs for second and higher degree digital differentiators for midband frequency ranges are proposed. Exact mathematical formulas for computation of the required weighting coefficients are also derived. The designs are capable of achieving extremely low relative errors (±1%-±0.001%) in the frequency range 0.25π⩽ω⩽0.75π with attractively low-order filters View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of CMOS circuits

    Publication Year: 1991 , Page(s): 83 - 90
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    The author presents a formal approach to the design of optimal CMOS networks by means of pass logic design techniques. Two approaches are given: one for CMOS pass networks and the other for CMOS gate networks. First, an overview of pass networks is given, and then methods for the design of optimal CMOS pass networks are presented. Different approaches are then presented for the design of CMOS gate networks. The designer is thus provided with a number of choices. The design of CMOS complementary logic, pseudo-nMOS logic, dynamic logic and domino CMOS uses the minterms and maxterms separately to form the network function, whereas cascode voltage switch logic (CVSL) uses them together. Finally, it is shown that optimal CVSL networks may not always be the best choice in terms of switching speed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved mixed-radix conversion for residue number system architectures

    Publication Year: 1991 , Page(s): 120 - 124
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Processor architectures, based on arithmetic cells using residue number systems, are inherently parallel, modular and fault isolating. The fundamental characteristic of a residue number system is its being an unweighted numbering system. The authors describe an improved technique for transforming a residue number into a mixed-radix weighted representation. The proposed conversion algorithm is based on the cyclic patterns inherent in residue number systems. The mixed-radix digits of the proposed conversion procedure are factorised into a product of two terms each: one term is invariant and predetermined, whereas the other is variable and depends upon the particular residue number being converted. In comparison with existing conversion techniques, the proposed conversion method achieves a considerable reduction in the number of arithmetic multiplications needed during the conversion process View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Two-dimensional off-state modelling of high-voltage semiconductor devices with floating guard rings

    Publication Year: 1991 , Page(s): 109 - 114
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The authors present novel algorithms for the off-state modelling of high-voltage devices with floating guard rings. The computation is based on quadratic isoparametric finite elements which improved accuracy in the determination of electric fields and ionisation integrals. The special boundary conditions for floating rings are considered together with an approach that automatically selects which ones to include in the calculations at a given bias. In addition, an efficient voltage-stepping technique is described for determining the breakdown voltage. Comparisons are made with measured values of floating ring potential and breakdown voltage on a variety of test devices with excellent agreement being found View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Statistical and numerical method for MOSFET integrated-circuit sensitivity simulation using SPICE

    Publication Year: 1991 , Page(s): 77 - 82
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    Circuit sensitivity analysis helps a circuit designer to determine which transistors in a circuit are most influential on its performance and how variations of the device and process parameters affect the circuit output responses. The authors present a systematic approach for analysis of metal-oxide-semiconductor field effect transistor (MOSFET) integrated circuit DC performance as a function of channel length and width variations. The method, which involves an algorithm based on the Tellegen theorem and a database that contains statistical information on MOSFET process parameters, is implemented in the widely used SPICE2 circuit simulator. Sensitivity simulation of a MOSFET operational amplifier is included to illustrate the usefulness of the method View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.