Surface Mount Devices Research Articles

Acoustic Wave Resonator-Based Absorptive Bandstop Filters With Ultra-Narrow Bandwidth

Ultra-narrowband absorptive bandstop filters (ABSFs) are presented in this letter. They are based on a hybrid RF-design approach in which high-unloaded quality-factor (Q) acoustic wave (AW) resonators and low-Q lumped-element components are effectively combined to create narrow <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({&lt;} 0.1\hbox{\%})$</tex> </formula> fractional-bandwidth (FBW) stopbands that exhibit theoretically infinite attenuation and effective quality factor <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(Q_{eff}$</tex></formula> ) of the order of a thousand. The proposed ABSF design approach is experimentally validated with two manufactured prototypes at 418 MHz that consist of commercially-available surface acoustic wave (SAW) resonators and surface mounted devices (SMDs). Measured FBWs as narrow as 0.02% that correspond to a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$Q_{eff}$</tex> </formula> of 10,000 and maximum stopband isolation of 68 dB validate the conceived ABSF design concept.

New technologies of multi-layered printed circuit boards, intended of rapid-design electronic modules

Purpose – The purpose of this study was the use of embedded components technology and innovative concepts of the printed circuit board (PCB) for electronic modules containing field-programmable gate array (FPGA) devices with a large number of pins (e.g. Virtex 6, FF1156/RF1156 package, 1,156 pins). Design/methodology/approach – In the multi-layered boards, embedded passive components that support FPGA device input/output (I/O), such as blocking capacitors and pull-up resistors, were used. These modules can be used in rapid design of electronic devices. In the study, the MC16T FaradFlex material was used for the inner capacitive layer. The Ohmega-Ply RCM 25 Ω/sq material was used to manufacture pull-up resistors for high-frequency pins. The embedded components have been connected to pins of the FPGA component by using plated-through holes for capacitors and blind vias for resistors. Also, a technique for a board-to-board joining, by using castellated terminations, is described. Findings – The fully functional modules for assembly of the FPGA were manufactured. Achieved resistance of embedded micro resistors, as small as the smallest currently used surface-mount device components (01005), was below required tolerance of 10 per cent. Obtained tolerance of capacitors was less than 3 per cent. Use of embedded components allowed to replace the pull-up resistors and blocking capacitors and shortens the signal path from the I/O of the FPGA. Correct connection to the castellated terminations with a very small pitch was also obtained. This allows in further planned studies to create a full signal distribution system from the FPGA without the use of unreliable plug connectors in aviation and space technology. Originality/value – This study developed and manufactured several innovative concepts of signal distribution from printed circuit boards. The signal distribution solutions were integrated with embedded components, which allowed for significant reduction in the signal path. This study allows us to build the target object that is the module for rapid design of the FPGA device. Usage of a pre-designed module would lessen the time needed to develop a FPGA-based device, as a significant part of the necessary work (mainly designing the signal and power fan-out) will already be done during the module development.

Reliability investigations on LIFT-printed isotropic conductive adhesive joints for system-in-foil applications

The reliability of a commercially available isotropic conductive adhesive (ICA) deposited via laser induced forward transfer (LIFT) printing is reported. ICAs are particularly important for surface mount device (SMD) integration onto low-cost, large-area system-in-foil (SiF) applications such as radio frequency identification (RFID) transponder tags. For such tags, and for SiF in general, the reliability of the printed interconnects under harsh circumstances is critical. In this study, the reliability of surface mounted resistors bonded onto screen-printed conductive circuitry on polymer foil was assessed. The prepared samples were subjected to thermal shock testing (TST), accelerated humidity testing (AHT) and flexural testing, while electrical measurements were conducted at regular intervals. Die shear testing was performed to evaluate the bond strength. The reliability characteristics of the LIFT-printed samples were benchmarked against current industry standard stencil printing process. Finally, the applicability of the LIFT–ICA process for practical applications is demonstrated using RFID transponder integration and testing.

Component pick and place scheduling for surface mount device placement machine

Component pick and place scheduling for surface mount device placement machine

Influence of the material composition on the environmental impact of surface-mount device (SMD) transistors

The aim of this study is to better elucidate the influence of surface-mount device (SMD) transistor material composition on the environmental impact of such transistors. A life cycle assessment (LCA) has been performed in which the EcoInvent dataset was updated with material compositions provided by several manufacturers. The influence of the material composition has been studied, providing a more precise understanding of the environmental impact. The software used to develop the LCA model was SimaPro 8.0.3.14, developed by Pré Consultants. The LCA was calculated with the CML methodology. In addition, a life cycle inventory was developed using EcoInvent v3.The EcoInvent methodology was used as a comparison tool for information provided by the manufacturers in terms of environmental impact, thus improving transistor selection in electronics design. The environmental impact of an SMD transistor can vary substantially with respect to material composition. Raw material acquisition represent between 20.3% and 99.9% of the total impact in most environmental categories. By contrast, the environmental impact of each transistor created due to part production is usually lower. The lowest environmental impact comes from the end of life treatments, values for which are approximately 0.1%.This environmental impact study demonstrates the large influence of transistor material composition for those analyzed herein.

High-efficiency and low assembly-dependent chip-scale package for white light-emitting diodes

This article presents a chip-scale package (CSP) with conformal and uniform structures for white light-emitting diodes used in lighting and backlight unit (BLU) applications. The CSP structures produce higher light extraction efficiency and lower assembly-dependent packaging compared with conventional surface-mounted devices (SMDs). Simulation results show that compared with SMDs, the luminous efficiency of CSP structures is 8.81% higher in lighting applications and 9.43% higher in BLU applications. This is likely due to light loss in the light bowl of the SMDs. Moreover, CSPs with a conformal phosphor structure exhibit low assembly dependence and redundancy, and rb-CSPs with a conformal structure are a more effective light source in both lighting and BLU applications.

신경회로망을 이용한 SMD 패키지의 자동 분류

This paper proposes a SMD (surface mounting device) classification method for the PCB assembly inspection machines. The package types of SMD components should be classified to create the job program of the inspection machine. In order to reduce the creation time of job program, we developed the automatic classification algorithm for the SMD packages. We identified the chip-type packages by color and edge distribution of the images. The input images are transformed into the HSI color model, and the binarized histroms are extracted for H and S spaces. Also the edges are extracted from the binarized image, and quantized histograms are obtained for horizontal and vertical direction. The neural network is then applied to classify the package types from the histogram inputs. The experimental results are presented to verify the usefulness of the proposed method.

RF rectifiers for EM power harvesting in a Deep Brain Stimulating device.

A passive deep brain stimulation (DBS) device can be equipped with a rectenna, consisting of an antenna and a rectifier, to harvest energy from electromagnetic fields for its operation. This paper presents optimization of radio frequency rectifier circuits for wireless energy harvesting in a passive head-mountable DBS device. The aim is to achieve a compact size, high conversion efficiency, and high output voltage rectifier. Four different rectifiers based on the Delon doubler, Greinacher voltage tripler, Delon voltage quadrupler, and 2-stage charge pumped architectures are designed, simulated, fabricated, and evaluated. The design and simulation are conducted using Agilent Genesys at operating frequency of 915 MHz. A dielectric substrate of FR-4 with thickness of 1.6 mm, and surface mount devices (SMD) components are used to fabricate the designed rectifiers. The performance of the fabricated rectifiers is evaluated using a 915 MHz radio frequency (RF) energy source. The maximum measured conversion efficiency of the Delon doubler, Greinacher tripler, Delon quadrupler, and 2-stage charge pumped rectifiers are 78, 75, 73, and 76 % at -5 dBm input power and for load resistances of 5-15 kΩ. The conversion efficiency of the rectifiers decreases significantly with the increase in the input power level. The Delon doubler rectifier provides the highest efficiency at both -5 and 5 dBm input power levels, whereas the Delon quadrupler rectifier gives the lowest efficiency for the same inputs. By considering both efficiency and DC output voltage, the charge pump rectifier outperforms the other three rectifiers. Accordingly, the optimised 2-stage charge pumped rectifier is used together with an antenna to harvest energy in our DBS device.

リードの周期性に着目した電子部品自動分類システム

This paper proposes a method for an automatic classification system of surface mount devices (SMDs) focused on the periodicity of leads. Automatic classification methods for the type of SMD are required as preprocessing for mounting SMDs in chip mounters. Due to the variations of connector parts, the previous method has a low accuracy rate. This paper presents a classification method for multiple types of SMDs by using Higher-order Local AutoCorrelation (HLAC) features from the power spectrum of an SMD image. Support Vector Machine (SVM) automatically classifies connector parts including the periodicity of leads by using HLAC features from a spectrum. The experimental results show that the proposed method improved the accuracy rate of the connectors (115 samples) from 40.0[%] to 91.3[%]. For all kinds of parts (748 samples), the accuracy rate was improved from 89.2[%] to 96.0[%].

Application of Adaptive Dead-beat Controller in Drying Process

In the article a temperature control is dealt in drying machines during a manufacturing process of printed circuits boards. A problem occurs if the temperature is not complied during a drying process of a solder mask and a service printing. It involves to depreciation of the printed circuit board, especially if the surface mount devices are used. An adaptive polynomial controller was designed to improve the temperature control. The controller is constructed by dead-beat method and it is implemented into 8-bit microcontroller, which has supervision of control process of whole drying system.The controller is based on a recursive identification algorithm, which identifies the dryer system. That identification proceeds continuously during the printed circuits boards drying process. Parameters of controller are recalculated in each period on the basis of data obtained by identification.

表面実装部品のリード形状データの自動生成

表面実装部品のリード形状データの自動生成

Influence of DC Bias on the Electrical Characteristics of SMD Inductors

As the dc bias flows through a ferrite chip surface mount device (SMD) inductor, it tends to premagnetize the core and reduce its inductance and impedance. It is observed that this drop is especially emphasized when the dc current exceeds the safety limit given by the manufacturer. Therefore, it is necessary to investigate and predict the degree of electrical characteristics degradation as well as the dependence of the core losses on core temperature. In this paper, a measurement technique for the investigation of the influence of dc bias on the electrical characteristics of SMD inductors (i.e., inductance, resistance, Q factor, and real and imaginary part of impedance) for printed circuit board applications is presented. Analysis is based on the model of the SMD inductor, which can be presented as a two-port equivalent circuit with intrinsic and extrinsic parameters. For calculation of the parameters of the SMD inductor, extracted from measured S-parameters using vector network analyzer, the in-house software tool IndCalc was used.

Silicon nitride, a high potential dielectric for 600 V integrated RC-snubber applications

Monolithically integrated RC-snubbers were realized by metal-insulator-semiconductor capacitors on a silicon substrate also serving as a series resistor. These devices provide a promising alternative to passive surface-mounted device components that are commonly used for snubber applications in power electronic circuits. The surface area of the substrate was enlarged with circular trench structures to increase the integration level of the capacitor, and a silicon nitride layer with a thickness of 1.05 μm was deposited on top of a 20 nm-thin silicon oxide layer as a potential dielectric for applications up to 600 V. With the trench geometry, a capacitance per surface area of 0.6 nF/mm2 was achieved, which is more than ten times the capacitance of a planar device using the same dielectric layers. However, combining the thick silicon nitride layer with the trench geometry caused an excessive wafer bow of nearly 800 μm, so deposition and structuring of a surface passivation layer, such as polyimide, was not feasible. Therefore, inert oil had to be used as a surface passivation for high voltage measurements. The silicon nitride dielectric exhibits a leakage current density lower than 0.3 nA/mm2 at the requested 600 V operating voltage, while dielectric breakdown of the devices is observed at 1050 V. A low deviation in capacitance and series resistance across the wafer and a high yield regarding the high voltage stability is achieved because of the good quality and homogeneity of the silicon nitride dielectric layer.

Photonic Flash Soldering of Thin Chips and SMD Components on Foils for Flexible Electronics

Ultrathin bare die chips and small-size surface mount device components were successfully soldered using a novel roll-to-roll compatible soldering technology. A high-power xenon light flash was used to successfully solder the components to copper tracks on polyimide (PI) and polyethylene terephthalate (PET) flex foils by using a lead-free solder paste. Results are compared with oven-reflowed solder joints on PI substrates. The delicate PET foil substrates were not damaged owing to the selectivity of light absorption, leading to a limited temperature increase in the PET foil while the chip and copper tracks were heated to a temperature high enough to initiate soldering. The microstructure of the soldered joints was investigated and found to be dependent on the photonic flash intensity. Reliability of the photonically soldered joints during damp heat testing and dynamic flexing testing was comparable with the reflowed benchmark and showed increased reliability compared with anisotropic conductive adhesives bonded on PET foils.

Construction of Highly Luminescent CdTe/CdS@ZnS–SiO2 Quantum Dots as Conversion Materials toward Excellent Color-Rendering White-Light-Emitting Diodes

Highly red-luminescent N-acetyl-l-cysteine-stabilized CdTe/CdS@ZnS–SiO2 quantum dots (QDs) were successfully synthesized in the aqueous phase via a promising microwave strategy for the first time; they were prepared by coating SiO2 layers doped with ZnS-like clusters on CdTe/CdS core/shell QDs. Owing to the effective passivation of the coating CdS shell and ZnS–SiO2 layer, the as-prepared QDs show high photoluminescence, good optical stability, and low biotoxicity. Moreover, the outermost SiO2 layer endows the QDs with excellent silicone compatibility. The structures and photoluminescence properties of the CdTe/CdS@ZnS–SiO2 QDs were well studied by various characterizations. For their practical applications, we explored the promising red-luminescent QDs as novel red phosphors to fabricate two types of white-light-emitting diodes (WLEDs), a low-power surface-mounted device and a high-power device. Both of the devices produce bright white light with remarkable color rendering. Especially, the color-renderin...

Defect Inspection for SMD Inductors

This paper presents a machine vision inspection method for winding high frequency inductors, which affects the reliability and quality of the electronic products. This paper proposes how to quickly and correctly improve the quality of component detection, an important issue for surface mounted device (SMD) inductors manufacturers. SMD components easily damage the phenomenon of the electrode, and the brightness of the brightness of the damaged area of the electrode close to normal, not easy to be precise defect area separated from the electrode area.

Comparing 2D and 3D numerical simulation results of gas flow velocity in convection reflow oven

Purpose – This paper aims to compare and study two-dimensional (2D) and three-dimensional (3D) computational fluid dynamics simulation results of gas flow velocity in a convection reflow oven and show the differences of the different modeling aspects. With the spread of finer surface-mounted devices, it is important to understand convection reflow soldering technology more deeply. Design/methodology/approach – Convection reflow ovens are divided into zones. Every zone contains an upper and a lower nozzle-matrix. The gas flow velocity field is one of the most important parameters of the local heat transfer in the oven. It is not possible to examine the gas flow field with classical experimental methods due to the extreme circumstances in the reflow oven. Therefore, numerical simulations are necessary. Findings – The heat transfer changes highly along the moving direction of the assembly, and it is nearly homogeneous along the traverse direction of the zones. The gas flow velocity values of the 2D model are too high due to the geometrical distortions of the 2D model. On the other hand, the calculated flow field of the 2D model is more accurate than in the 3D model due to the finer mesh. Research limitations/implications – Investigating the effects of tall components on a printed wiring board inside the gas flow field and further analysis of the mesh size effect on the models. Practical implications – The presented results can be useful during the design of a simulation study in a reflow oven (or in similar processes). Originality/value – The presented results provide a completely novel approach from the aspect of 2D and 3D simulations of a convection reflow oven. The results also reveal the heat transfer differences.

A vision-based LED defect auto-recognition system

Recognising different kinds of light-emitting diode (LED) defect is of great urgency for online manufacturers because such information not only assists in summarising the production variations but also in realising that the defects are caused either by fabricating process or by taping process. Although most of the studies nowadays engage in devising LED defect auto-inspection systems, they are rarely capable of auto-recognising the type of defects simultaneously. This study developed a vision-based defect auto-recognition system for three types of packaged surface-mounted device LEDs. A series of image processing are implemented to obtain the inherent feature of the LEDs. Then, a two-stage multiple discriminant analysis is used to recognise different kinds of defects. The recognition rates of up to 94.34% of LED1S, 95.17% of LED1B and 96.02% of LED2 are yielded, which demonstrate the efficiency and effectiveness of the proposed system.

An Inspection Method of SMD Component Type Based on Moment Features and BP Neural Network

The type inspection of surface mounted devices (SMD) components is an important part of the numerical control (NC) placement machine’s vision system. In order to improve the detection speed, accuracy rate and versatility, a detection method based on moment features and neural network is proposed. Firstly, component images are preprocessed in order to eliminate the influence of non-uniform illumination and simplify the calculation, so component lead images can be obtained, and then seven invariant moments and a zero-order Zernike moment of the lead images are extracted. Next, the moment features are corrected and normalized. Finally, back propagation (BP) neural network based on the Levenberg-Marquardt algorithm is taken as a classifier for training and testing the 8-dimensional mixed moment feature vectors, 0 and 1 are used to represent the degree of belonging of each image. The experimental results show that this method doesn’t need complex lighting system and has good versatility, and the correct rate can be up to 100%.

Broadband Differential Phase-Shifter Design Using Bridged T-Type Bandpass Network

In this paper, a family of broadband differential phase shifters using bridged T-type bandpass networks and their design procedures are presented. Conventional high/low-pass networks are widely applied in 22.5 °-90 ° phase shifters. However, the tradeoff must be made between the bandwidths of return loss and phase error, which are limited to less than 90%. The proposed bridged T-type bandpass network can improve the bandwidth of phase error while keeping good return loss. Theoretically, the fractional bandwidth of a phase shifter using a bridged T-type bandpass network can be improved by more than 40 percentage points as compared with a conventional high-pass network. 22.5 °, 45 °, and 90 ° phase shifters are demonstrated on FR4 using discrete surface mounted device (SMD) L/C components. Due to limited discrete SMD component values, the phase and return-loss bandwidths of the realized three phase shifters are slightly reduced, but still larger than 125% and are better than 18 dB from 0.55 to 2.51 GHz.