Manufacturer Datasheet Research Articles

Modeling of RF Absorber for Application in the Design of Anechoic Chamber

A proper model of RF absorber must be developed based on information such as absorber reflectivity, in magnitude and phase, for various angles of incidence, and for parallel and perpendicular polarizations. Unfortunately, these data are not available due to the practical limitations of the test fixtures to measure the RF absorber performance. Manufacturer data sheets normally specify only the magnitude of the absorber reflectivity for normal incidence. A model has been developed in this paper for pyramidal RF absorber with pyramid length shorter than a quarter wavelength and poor reflectivity performance. Since the reflection from the metal backing would be much higher than the reflection and scattering from the pyramid tips, the metal boundary may be modeled as a lossy dielectric with certain effective dielectric constant, e eff , and effective conductivity, σ eff , and the thickness extends to infinity. The appropriate values of e eff and σ eff can be derived based on the reflectivity information given by the manufacturer's data sheet. The reflectivity at oblique incidence is calculated and compared with the results of method of homogenization and moment method. A reasonable match between the different models is obtained. The plane-boundary dielectric model can be used to evaluate the degradation of reflectivity level with respect to angle of incidence. It can be used in a simulation tool for design of anechoic chamber.

Developing an advanced PWM-switch model including semiconductor device non-linearities

The accurate simulation of power electronic systems is possible when including accurate models of the semiconductor devices, but practically not affordable. Classical ideal averaged models of the system are not suitable either. Hence, averaged models including the non-linear effects of the power semiconductor devices appear quite efficient. The proposed non-ideal PWM-switch model is a useful method for modeling pulse width modulated converters operating in the continuous conduction mode. The main advantages of the proposed averaged model are the takes into account of the non-linear effects of power devices and the possibility to estimate the dissipated power in the different circuit devices. The proposed electrical model can be applied to bi-directional converters and allows the coupling with thermal model in the power electronic system. A simple technique to evaluate the different static and dynamic parameters of the devices, from manufacturers data sheets or experimentally, is presented.

Clinicopathologic implications of E‐cadherin reactivity in patients with lobular carcinoma in situ of the breast

Clinicopathologic implications of E‐cadherin reactivity in patients with lobular carcinoma in situ of the breast

GTO Device Model for SPICE Usable for Evaluating the Effect on Drive Circuit

This paper proposes a new GTO model for drive circuit design. The proposed model is easy to use for GTO consumers, because the model parameters are easily obtained from the manufacturer's data-sheet and some simple measurements. In this paper, the authors demonstrated the model by comparison of simulation and experimental result. These results show good performance of the model for designing drive circuit.

The effects of curing parameters on the properties development of an epoxy encapsulant material

The results of a series of experiments aimed at identifying optimal processing windows for a model epoxy-based encapsulant material used in integrated circuit packages are reported in this paper. Several key material characteristics were evaluated as a function of processing conditions, including glass transition temperature ( T g), coefficient of thermal expansion, flexural strength, flexural modulus, ultimate flexural strain, and package warpage. The processing variables evaluated included cure temperature, cure time, type of cure schedule (single step, two step, or discontinuous). These results confirm that alternative cure schedules to those reported on manufacturer's data sheets are often available that provide an acceptable balance of material properties for specific applications.

Book Review: The Pocketbook of Drug Eruptions and Interactions, 2nd edition

Dermatologists are all too familiar with the challenge presented by an ill patient on a medical or surgical ward whose condition is compounded by an extensive rash; is it a drug eruption and if so which of the patient's recent or current medications is at fault? The unravelling of such a puzzle is rarely assisted by the manufacturer's data sheet, which almost inevitably lists `rash' among a long list of potential side-effects and adverse reactions. Helpful information is indeed remarkably difficult to find. In a very few instances we now know why some people react adversely to a medication and others do not; marrow suppression from azathioprine, for example, is known to be almost entirely confined to those who lack the enzyme thiopurine methyltransferase (which can be readily measured). Occasionally the pattern of eruption is distinctive, as in fixed drug eruption, or erythema multiforme. Sometimes a pattern of adverse reaction may be predicted; for example, since penicillamine can induce a pemphigus-like eruption we might expect the structurally related molecule captopril to do likewise.

Thermal instability of low voltage power-MOSFETs

This paper analyzes an anomalous failure mechanism detected on last generation low voltage power metal oxide semiconductor (MOS) devices at low drain current. Such a behavior, apparently due to a kind of second breakdown phenomenon, has been scarcely considered in literature, as well as in manufacturer data sheets, although extensive experimental tests show that it is a common feature of modern low voltage metal oxide semiconductor held effect transistor (MOSFET) devices. The paper starts by analyzing some failures, systematically observed on low voltage power MOSFET devices, inside the theoretical forward biased safe operating area. Such failures are then related to an unexpected thermal instability of the considered devices. Experimental tests have shown that in the considered devices the temperature coefficient is positive for a very wide drain current range, also including the maximum value. Such a feature causes hot spot phenomena in the devices, as confirmed by microscope inspection of the failed devices. Finally, it is theoretically demonstrated that the thermal instability is a side effect of the progressive die size and process scaling down. As a result, latest power MOSFETs, albeit more efficient and compact, are less robust than older devices at low drain currents, thus requiring specific circuit design techniques.

A Screening Method for Occupational Reproductive Health Risk

Most currently recognized occupational exposure limits do not consider reproductive toxicological end points consistently when establishing recommended exposure limits. In many cases the information is not available, but perhaps as often, existing data is not employed. Further, many manufacturer's material safety data sheets omit reproductive hazard information. A method for identifying potential reproductive toxins and screening levels for associated health risks useful for hazard communication and exposure control is presented. To date, the Registry of Toxic Effects of Chemical Substances lists between 5000 and 6000 chemicals, drugs, and natural substances that show a positive outcome in at least 1 reproductive effects study. This reproductive health risk assessment began with these substances. Using elements of the Environmental Protection Agency's health risk assessment process, the list was reduced to 213chemicals during the hazard identification step. Occupational reproductive guidelines (ORGs)were developed in the dose-response evaluation step. At the time of this writing, 85% of the chemicals identified in the hazard identification step have had a screening level dose–response assessment completed. Of these, 13% are greater than or equal to a threshold limit value (TLV®). The remaining 87% do not have a TLV or ORGs below the TLV. The reproductive toxins list, along with the corresponding dose–response–derived ORGs that have been completed, appears at the end of the text.

A screening method for occupational reproductive health risk.

Most currently recognized occupational exposure limits do not consider reproductive toxicological end points consistently when establishing recommended exposure limits. In many cases the information is not available, but perhaps as often, existing data is not employed. Further, many manufacturer's material safety data sheets omit reproductive hazard information. A method for identifying potential reproductive toxins and screening levels for associated health risks useful for hazard communication and exposure control is presented. To date, the Registry of Toxic Effects of Chemical Substances lists between 5000 and 6000 chemicals, drugs, and natural substances that show a positive outcome in at least 1 reproductive effects study. This reproductive health risk assessment began with these substances. Using elements of the Environmental Protection Agency's health risk assessment process, the list was reduced to 213 chemicals during the hazard identification step. Occupational reproductive guidelines (ORGs) were developed in the dose-response evaluation step. At the time of this writing, 85% of the chemicals identified in the hazard identification step have had a screening level dose-response assessment completed. Of these, 13% are greater than or equal to a threshold limit value (TLV). The remaining 87% do not have a TLV or ORGs below the TLV. The reproductive toxins list, along with the corresponding dose-response-derived ORGs that have been completed, appears at the end of the text.

Measurement and modelling of operational amplifier power supply rejection

A new approach to the measurement of operational amplifier power supply rejection, based on the measurement of the power supply injected signal gain of a high-gain differential amplifier configuration, is presented. Measured results for 741 and pin-compatible operational amplifiers are tabulated. A new SPICE macromodel which models operational amplifier power supply rejection characteristics is described. Design equations are provided to extract macromodel parameters from manufacturer's data sheets or measured power supply rejection data. Good agreement has been found between measured operational amplifier power supply rejection characteristics and simulated circuit performance based on the new macromodel.

Impact of IGBT behavior on design optimization of soft switching inverter topologies

IGBTs operated under a zero voltage switching scheme exhibit significantly different operating characteristics from specified parameters in manufacturer data sheets. Important differences include an elevated tail current, dynamic saturation and resulting snubber dump, and a significantly higher conduction loss under moderate to high di/dt conditions. Soft switching inverter topologies of various kinds have been reported in the literature including resonant DC and AC link inverters, resonant pole inverters and many variations thereof. Loss characterization of soft switching inverter circuits reported to date is based on manufacturer data sheets, and do not reflect actual losses incurred in the circuit. Including the actual device behavior into the circuit loss calculations has a big impact on the total losses, and more importantly the trade-offs which impact the viability of a given topology at a specified operating point. This paper presents a detailed analysis of the losses in soft switching inverters and the impact on topology choice. A detailed design of a 50 kVA IGBT-based resonant DC link inverter is used as a design example, and it is seen that optimal design points and choices are significantly different from those that have been reported earlier.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Neurotoxicity of Acyclovir in Patients With End-Stage Renal Failure Treated With Continuous Ambulatory Peritoneal Dialysis

We report two cases of herpes-zoster in which the administration of acyclovir to patients with end-stage renal failure treated by continuous ambulatory peritoneal dialysis (CAPD) resulted in acyclovir neurotoxicity, even though the doses administered were within those recommended by the manufacturer's data sheet for patients with renal failure. Acyclovir removal was negligible with peritoneal dialysis and one patient died. The other patient was successfully treated with hemodialysis, which effectively reduced plasma concentrations, resulting in an improvement in conscious state. Acyclovir neurotoxicity should be considered in patients with renal failure who have been treated for viral infections, in whom the conscious state has deteriorated despite normal brain computed tomography (CT) scan and lumbar puncture investigations. Hemodialysis is the preferred treatment for the rapid removal of acyclovir.

A nonideal macromodel of thyristor for transient analysis in power electronic systems

A nonideal SCR (silicon controlled rectifier) macromodel for analog power circuit simulation using SPICE has been developed. This model adds important second-order effects such as overvoltage and critical dV/sub Ak//dt switch-on, turn-on, and tq times, threshold gate trigger voltage, and nonlinear on-state characteristics. The parameters of any specific SCR can be easily obtained from its data sheet specifications. Any kind of thyristor, from high power up to fast turn-off, can be modeled with only 10 well-defined parameters. Electronic systems with electrical transients can be successfully simulated. Good agreement between manufacturer data sheet specifications and simulated results has been observed for all the thyristors considered.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Determination of thyristor reverse recovery current parameters

This paper describes a method of determination of reverse recovery current parameters of the thyristor turnoff model, namely, the peak reverse recovery current and its decay time constant. The parameters are determined from a set of recovered charge curves, and another set of reverse energy loss curves, usually given in the manufacturer's data sheet so that the curves may be fitted over a wide range of di/dt at zero current and peak forward thyristor current IF, just before its current reversal. In the parameter extraction, the storage time and the ratio of fall time to storage time were assumed to be functions of di/dt and IF. For various thyristors, the extracted parameters fit both sets of the above-mentioned curves within an error of 8% over a 1:100 ratio of di/dt at zero current and over a 1:4 ratio of IF.

Optimum noise source impedance determination for GaAs FETs at room and cryogenic temperatures

Abstract An analytical technique is developed to determine the optimum noise source impedance for an extrinsic, or packaged, gallium arsenide field-effect transistor (GaAs FET) using only the small-signal s-parameters and the minimum noise figures available from the manufacturer's data sheet. The procedure is then modified to treat the special case of the intrinsic, or chip, GaAs FET as well. The technique is then extended to determine the optimum noise source impedance and minimum noise figure at cryogenic temperature using the room temperature results. The procedure is used to determine the optimum noise source impedance of a Mitsubishi MGF-1412 and a Mitsubishi MGFC-1412 at room and cryogenic temperature. At room temperature and 4 9 GHz, the technique yields an optimum noise source impedance of 28·4 ft -Ω64·1 Ω for the extrinsic device as compared with the measured optimum noise source impedance of 20 Ω + j55Ω. At cryogenic temperature, the optimum noise source impedance obtained is 21·1 Ω + j70·8 Ω as...

Noise models for gallium arsenide field-effect transistors at room and cryogenic temperatures

An analytical technique is developed to determine the optimum noise source impedance for a chip gallium arsenide field-effect transistor (GaAs FET) using only the small-signal s-parameters and the minimum noise figures available from the manufacturer's data sheet. The technique is then extended to determine the optimum noise source impedance and minimum noise figure at cryogenic temperatures using the room temperature results. The procedure is used to determine the optimum noise source impedance of a Mitsubishi MGFC-1412 at room and cryogenic temperatures. At room temperature, the technique yields an optimum noise source impedance that is 16% in error as compared with the measured optimum noise source impedance. At cryogenic temperatures, the result is in error by 19% for the real part and by 9% for the imaginary part as compared with the available experimental value, and by 7% for the real part and by 12% for the imaginary part as compared with a more rigorous theoretical result.

Manufacturers' catalogues and data sheets

Manufacturers' catalogues and data sheets

CASS8: A cross assembler suitable for most of the 8 bit microprocessors

In order to allow students to experiment, at the assembler level, with various microprocessors, a “universal” cross assembler was designed. The instruction set for a particular microprocessor is a data file, the cross assembler has to read before assembling programs. The cross assembler produces a source listing completed by the generated object code or by error messages. The listing is ideal for handloading the microprocessors through standard debugging monitors. For loading longer programs, special debugging monitors were developed for the most popular microprocessors, allowing direct loading by the host computer. The data file describing the instruction set of a microprocessor is easily prepared from the manufacturer data sheets, the mnemonics being unaltered, or undergoing only short modifications.

Transient response of vidicon photoconductors

An expression for the rise and decay times of vidicon photocurrents as a function of incident illumination is derived for a certain class of vidicon photoconductors. The approach taken is semiempirical in that certain parameters in the derived expression are obtained directly from vidicon manufacturer's data sheets. Regults compare well with the manufacturer's published results.

Performance Studies of Photomutipliers Having Dynodes with GaP(Cs) Secondary Emitting Surface

Characteristics of photomultipliers having dynodes with cesium-activated gallium phosphide secondary emitting surfaces have been investigated. We present measurements of characteristics, generally not available from manufacturers data sheets, for several 8850's, C70133B's, 8852's, and C31024's. The transit-time difference, the single-electron transit-time spread, and the collection and quantum efficiency uniformity as a function of the position of the photocathode sensing area are measured and discussed. Measurement techniques and descriptions of measuring systems are given in detail. Ephasis is put on the determination of optinum photamultiplier operating conditions, particularly concerning the collection efficiency, and minimum transit-time spread.