混合微电路用多芯组瓷介电容加固技术

多芯组瓷介电容具有单位安装面积容量大、抗机械应力强、等效串联电阻低等优点,在混合电路中具有很大的应用前景.简述了多芯组瓷介电容的工艺结构,通过仿真分析以及试验验证,确定了一种多芯组瓷介电容的加固方式,解决了多芯组瓷介电容在混合电路中安装可靠性低的问题.     

高可靠DC-DC混合电源长寿命评价技术研究

随着科学技术的发展、设计和制造水平的大幅度提高,高可靠长寿命DC-DC混合电源产品在军事及航空航天领域应用越来越广泛,如何预测其寿命是值得深入研究的重要问题。采用加速退化试验方法,对一款高可靠DC-DC混合电源进行可靠性评价与寿命预测。此研究成果对解决高可靠性电源产品的可靠性保证和寿命预测问题具有很好的工程意义。     

瓷介电容在广播电视信号传输处理电路中的应用经验

0 引言瓷介电容分为一类瓷介电容和二类瓷介电容,在广播电视电路中的应用范围包括一类(CG):谐振回路、高频耦合、高频放大器、低噪声电路、高频旁路以及要求低损耗、电容量高稳定和绝缘电阻高的电路,二类(X7R或X5R):电源滤波、旁路、低频耦合电路或对损耗和电容量稳定性要求不高的电路中。     

陶瓷电容在EMI滤波器中的应用研究

电容是EMI滤波器中的重要元件,本文首先介绍了电源EMI滤波器的基本电路形式和工作原理,给出了滤波器中对电容的基本要求,重点介绍了陶瓷电容的等效电路和基本特性,强调了陶瓷电容在厚膜混合集成电路中的工艺处理要求,最后给出了在电源EMI滤波器中使用陶瓷电容的几点注意事项。     

基于退化数据的厚膜电阻可靠性评估

设计了厚膜电阻的高温贮存试验,以评估厚膜电阻的可靠性。基于阻值的退化数据,采用线性退化模型描述厚膜电阻的退化过程,结果表明,厚膜电阻伪寿命分布满足对数正态分布规律。结合Arrhenius模型推算得出,厚膜电阻在室温下的寿命约为17.8年。分析了厚膜电阻的失效机理,完成了厚膜电阻在温度应力下的可靠性评估。     

Digital彩显三无故障维修二例

<正> [例1]故障现象 三无。 分析与检修 打开显示器后盖,发现保险管已烧断,断定电源有短路故障。用万表R×1挡测量电源滤波电容C908两端,电阻接近0Ω,焊下整流桥堆D901及滤波电容C908检查均正常。在线测量厚膜块IC901(STR 55717)①脚与③脚电阻为零,怀疑厚膜块IC901损坏,用同一型号换上后,开机显示正常。     

绿色混合数字计算机电源管理

图1所示的模拟电源解决方案是一种众所周知和经过实践检验的技术,功率电子工程师在时域中理解起来毫不费力。模拟PWM控制器包括一个误差放大器,用一些电阻和电容构成补偿网络。通过对电阻和电容值进行微调可实现最佳性能。模拟PWM控制器提供快速和准确控制,人们开发了许多先进的     

MCM-C中厚膜电阻的寿命分布及退化规律的研究

重点研究了MCM-C基板的可靠性，包括厚膜电阻、基板布线以及互连通孔。试验采取加温度应力与电应力的双应力加速寿命试验。试验中发现，厚膜电阻的退化先于基本布线和互连通孔，故厚膜电阻的退化在MCM-C基板可靠性中起主要的作用；重点讨论了厚膜电阻在热电应力下的失效规律及寿命分布，试验结果表明厚膜电阻的寿命分布服从威布尔分布。     

基片作电容介质碳树脂作电阻的厚膜电路

<正> 国内的厚膜电路大多采用丝网印刷方法,在低介电系数氧化铝陶瓷基片上制作导体和电阻,外贴电容和晶体二极管、三极管、芯片,制成混合集成电路。这种传统的厚膜工艺生产效率低,影响了成本的下降。笔者在国外样品的启发下,用基片兼作电容器介质,碳树脂作电阻,设计试制了一种新的低成本厚膜阻容网络,应用于高频振荡     

厚膜电阻的阻抗与驻波比频率特性的新测量方法

随着电子信息技术和移动通信技术的发展,厚膜电阻的应用越来越广泛。然而,如何准确测量厚膜电阻的阻抗和驻波比频率特性成为了一个难点。建立和分析微带线终端加载厚膜电阻的电路模型,使电阻在电路中匹配,再对应地建立终端短路的电路,最后联合求解出厚膜电阻的阻抗和驻波比频率特性。实测表明,这种测量方法是可行、准确的,对射频厚膜电阻的制造工艺和质量检测有着重要意义。     

厚膜片式电阻器硫化机理及失效预防

通过DC/DC模块电源失效分析和电阻硫化实验,采用扫描电镜和能谱分析等手段,研究了厚膜片式电阻器的硫化机理。结果表明:厚膜片式电阻器端电极和二次保护包覆层之间存在缝隙,空气中的硫化物通过灌封硅胶吸附进入到厚膜片式电阻器内电极,导致内电极材料中的银被硫化,生成电导率低的硫化银,从而使电阻的阻值变大甚至开路。结合DC/DC模块电源提出了几种预防电阻硫化的措施。     

激光微细熔覆电阻浆料直写电阻技术初步研究

应用一种新工艺——激光微细熔覆电阻浆料直写电阻技术,在陶瓷基板上制备厚膜电阻。介绍了新工艺研究的初步成果,及激光直写的附着机理,并展示了部分线电阻及通过搭接获得的电阻图案。重点讨论工艺参数的影响,研究了预置膜层厚度、激光功率和激光扫描速度对电阻线宽的影响规律。     

多层陶瓷电容器的发展及其动向

小型、低压、大容量化，片式高压系列化和低成本化是当前多层陶瓷电容器的主要技术发展趋势；移动通信设备和开关电源等产品是其应用的热门。瓷膜材料的面世，符合多层陶瓷电容器的低成本、小型和大容量化的发展潮流，将会取得推广与应用。     

Miniature hybrid microwave ICs using a novel thin-film technology

A novel thin-film technology for miniature hybrid microwave ICs is presented. All passive components, such as resistors and capacitors, are fully integrated on ordinary alumina ceramic substrates using the thin-film technology with very high yield. The numbers of parts and wiring processes were significantly reduced. This technology was applied to the fabrication of Ku-band solid-state power amplifiers. This thin-film technology offers the following advantages: (1) a very high yield fabrication process for thin-film capacitors having excellent electrical characteristics in the gigahertz range (ε=3.6, Q=230 at 12 GHz) and reliability; (2) two kinds of thin-film resistors having different temperature coefficients of resistivity (TCRs) and a lift-off process to integrate them with thin-film capacitors; and (3) a matching method using the thin-film capacitor     

Thick films or thin?

It is sometimes difficult to decide between thick-film and thin-film technologies in the fabrication of hybrid integrated circuits consisting of a ceramic substrate with deposited passive components and attached active devices. In the case of thick films, the deposited pattern of conductors, resistors, capacitors, and inductors is applied to the substrate by screen-printing and firing special conductive, resistive, or dielectric pastes. Thin-film layers, on the other hand, are deposited in vacuum by evaporation or cathode-sputtering of appropriate source materials. This article discusses the advantages and disadvantages of both technologies as well as their application ranges.     

搭接量对激光微细熔覆柔性直写厚膜电阻组织性能的影响

采用激光微细熔覆柔性卣写技术在陶瓷基板上制备厚膜电阻。该技术的优点是精度高、速度快、不需要制作掩模板等。大量研究结果表明．搭接量的改变对电阻的组织性能影响很大，而组织性能对最终整个器件的质量起决定作用。因此，获得最佳搭接量制备出性能优良的电阻元件成为重要的研究课题。针对陶瓷基板，系统地研究了搭接量对厚膜电阻的组织性能的影响规律，获得了形成电阻膜的最佳搭接量为单道扫描光斑直径的3／5，并对影响组织性能的主要机理进行了分析。     

High-temperature storage and thermal cycling studies of thick filmand wirewound resistors

The operating ambient temperature for underhood automotive and aerospace applications is increasing. This work was undertaken to evaluate the suitability of thick film and wirewound resistors for distributed aircraft control systems in a 200°C-225°C operating environment. High temperature stability testing of power wirewound and thick film resistors is reported. Dale power wirewound 1 Ω, 100 Ω, and 10 kΩ resistors with power ratings of 5 W and 25 W were tested. The TCR of the 100 Ω, and 10 kΩ resistors was very small, however, the 1 Ω resistor varied by 5% over the temperature range from 25°C to 300°C. Stability with long term storage (10000 h) at 300°C was measured for the wirewound resistors unpowered and powered at 20% of rated power. With the exception of the 10 kΩ/25W resistor, the change in resistance was less than 4%. Wirewound resistors were also thermal cycled 1000 times over a temperature range from -55°C to 225°C with only one failure due to a broken internal connection. Three 900 Series thick film resistor pastes from Heraeus-Cermalloy were studied: 100 Ω/sq., 1 kΩ/sq., 10 kΩ/sq. The temperature coefficient of resistance (TCR) was measured from 27°C to 500°C in 50°C increments. The change in resistance was <±6% up to 300°C. A 2 × 2 matrix of variables was included in the 300°C storage test: untrimmed resistors, resistors trimmed up 50% in value, unpowered, and powered at 1/8 W. Palladium/Silver was the initial termination choice for these 300°C studies, but silver migration under electrical bias lead to electrical shorts between conductor traces on the substrates with powered resistors. Gold terminated thick film resistors were used for powered storage testing at 300°C. The change in resistance after 10000 h at 300°C was < 3% for all test combinations     

一种使用LTPS TFT的新型DC-DC转换器

一种新型DC-DC转换器可整合在使用多晶硅薄膜晶体管的2．2inQVGA级LCD显示板上。为了给显示板提供正负电源，采用了多相DC—DC转换器结构，同时减小了充电泵的工作频率。所以显示板工作信号频率低于20 kHz，不需要外部时钟脉冲信号和电容。