Conductive Epoxy Attachment of Capacitors Written By: Ron Demcko | Ashley Stanziola Abstract: Compared to the vast majority, capacitor attachment via conductive epoxy is not a common technique among end-user applications. A significant amount of growth in capacitor usage has occurred in solder attachment methods. Furthermore, many publications on attachment methods focus predominantly on optimizing the multiple methods of solder component attachment. Therefore, confusion exists on the requirements needed to ensure reliable long-term attachment when using conductive epoxy material systems. This paper serves as a general introduction to conductive adhesives. It aims to assist end-users in the conductive epoxy attachment of SMT (Surface Mount Technology) components.
The Pros and Cons of MLCC Downsizing Written By: Frank Hodgkinson | Maureen Strawhorne Abstract: As integrated circuits (ICs) continue to pack more functionality into smaller packages, the need for bulk off-chip capacitance remains. In resonant circuits, such as phase-lock-loops (PLLs) and switching regulators, precision class one ceramic capacitor may be required. Such capacitors must maintain a tight capacitance range over process, voltage, and temperature variation (PVT) for the host IC to meet its performance specifications. In contrast, class two ceramic capacitors are required for nearly every IC in the form of decoupling and bypass capacitance. They may also be found in amplifier circuits, simple filters, and linear regulators where their function is less dependent on tightly specified impedance requirements.
The Application of Capacitors in Power Supply Regulator Circuits Written By: Rick Liu Abstract: Advancements in electronic technology over the last decade have led to smarter consumer electronics. As devices become smarter, the components used to power them are shrinking, resulting in small, but incredibly powerful devices — ones small enough to fit inside a pocket or around a wrist. With these smaller, denser designs, it can be impossible to separate analog and digital domains in the layout, as best practices used to dictate years ago. Today, design engineers are compelled to use many capacitors in the power network to attenuate high-frequency digital noise. Circuits are designed to expect pure, clean power without noise that will impact analog circuits.
AVX MLCC Flexiterm™: Guarding Against Capacitor Crack Failures Written By: Mark Stewart Abstract: The huge popularity of MLCC capacitors in comparison with alternative technologies is primarily a result of their superb reliability record and low cost. However, in certain circumstances problems can occur due to cracking in the ceramic portion of the component. These failures result from mechanical damage caused after soldering to the PCB; normally a consequence of PCB mishandling or when the assembly is located in extreme environmental conditions. This article outlines the main benefits and features of AVX’s ‘FlexiTerm™,’ a soft termination system that minimizes these failures by relieving the mechanical stress applied to the ceramic.
MLCC & TANTALUMINTERCHANGEABILITY Tantalum chip and Hi CV MLCC have a large degree of overlap in available capacitance ratings in common footprints. As MLCC production increased, many applications converted from tantalum to MLCC for many filtering, bypass, and hold-up applications. With the increasing demands seen for low voltage digital applications, tantalum electrolytic technologies have become a first choice for MLCC substitution. AVX is a leading international manufacturer and supplier of a wide range of advanced electronic components, including: capacitors, inductors, filters, and circuit protection devices. The AVX tantalum electrolytic division has maintained a leadership position in automotive, industrial, medical, space, military, consumer electronics, communications, and transportation markets for nearly 50 years. Maximum Available Capacitance by Case Size (6.3V): IPC has
Young’s Modulus and Thermal Diffusivity Measurements of Barium Titanate Based Dielectric Ceramics Written By: G. S. White and C. Nguyen National Bureau of Standards Gaithersburg, MD 20899 Bharat Rawal AVX Corporation Myrtle Beach, SC 29577 Abstract: Young’s modulus and thermal diffusivity values have been obtained on a set of barium titanate based ceramics using ultrasonic pulseecho and photoacoustic effect (PAE) measurements. The PAE was shown to detect variations in thermal diffusivity between materials of varying composition and processing treatments. The results are valuable in the evaluation of dielectric ceramic materials for practical electronics applications.
Surface Mount Soldering Techniques and Thermal Shock in Multilayer Ceramic Capacitors Written By: John Maxwell Abstract: All components used in surface mount assemblies have temperature processing limitations that must be adhered to for maximum reliability. This paper discusses multilayer ceramic capacitors in detail and soldering process considerations that are valid for all SMT components.
Some Observations on Recent MLCCs Quality as Experienced in Europe Including Discussion of Two Types of Dpa Analysis Written By: Dr. Phil Ward Abstract: A study of the European MLC quality by two types of DPA analysis shows that the newer formulations of 2F4 (Z5U) are as reliable as C0G (NP0) and 2C1 (X7R) formulations. These newer 2F4 formulations have small grain structure and low porosity which perform excellent on life test at 2xRV and load humidity 85ºC/85% RH at RV.
Reliability of MLCCs After Thermal Shock Written By: Bharat S. Rawal | Michael Childs | Allan Cooper | Bill McLaughlin Abstract: With increasing use of multilayer ceramic capacitors in surface mount applications, the understanding of thermal shock properties of these devices is becoming increasingly important. Of the various soldering techniques utilized in surface mount applications, including wave soldering, vapor phase and infra red reflow techniques, wave soldering imposes the most severe thermal stresses on the MLCs. To simulate this process, parts are often dipped in solder baths. It will be shown in this paper that properties like critical stress intensity factor K1C, thermal diffusivity, Young’s modulus and the chip geometry are important for understanding the thermal shock behavior of chips.
Reliability and Characterization of MLCC Decoupling Capacitors With C4 Interconnections Written By: Donald Scheider | Donald Hopkins | Paul Zucco | Edward Moszczynski | Michael Griffin | Mark Takacs IBM Microelectronics Division Hudson Valley Research Park 1580 Rte. 52, Hopewell Jct., NY 12533 John Galvagni AVX Corporation 2200 AVX Drive Myrtle Beach, SC 29577 Abstract: Multilayer ceramic (MLC) capacitors are composite structures made of alternating layers of ceramic (dielectric material) and metal (electrodes). The dielectric material is barium titanate-based ceramic and the electrodes are made of platinum. C4 (controlled collapse chip connections) technology  is used to provide multiple attachment points to substrates. A high dielectric constant of barium titanatebased ceramic helps to achieve a large capacitance/size ratio. The capacitance