Technical Library | 2010-03-23 11:50:22.0
This document discuss how to design SMT stencil base on IPC-7525. Introduction: PCBA (Printed Circuit Board Assembly) is a segment of printed circuit board technology. This segment of printed circuit board industry is concentrated in assemble all the pieces of electronic industry to one piece before output them to market. This segment covers: interconnection technology, package design technology, system integration technology, board and system test technology
Technical Library | 2012-12-26 14:18:24.0
Passive components including resistors, capacitors, inductors, and circuit-protection devices compose the highest percentage of all devices that are populated on today’s PCB assemblies. However, the successful isolation and testing of these components during ICT is perhaps the most challenging and the least understood of all modern-day validation practices.
Technical Library | 2012-02-09 15:26:56.0
The Fundamentals of Signature Analysis Technical document discusses the basics of power-off analog signature analysis, how it relates to basic electronic devices and how it is used for circuit board troubleshooting.
Technical Library | 2010-11-04 19:56:25.0
Conductive Adhesives represent an intrinsically clean, simple and logical solution for a myriad of electrical interconnect challenges. Adhesives not only provide a "lead-free", "no clean" alternative to solder, these highly compatible materials offer viab
Technical Library | 1999-07-20 10:35:30.0
Circuit simulation is a necessary everyday tool to circuit designers who need to constantly verify and debug their circuits during the design process. As engineers face larger, more complex designs and tighter project schedules, fast SPICE simulation with no loss in accuracy has become a necessity. Simulation indeed accounts for a large portion of the time spent in the design and optimization of a new circuit...
Technical Library | 2012-01-19 19:14:49.0
The history of multilayered, three-dimensional monolithic microwave integrated circuit (3-D MMIC) technology is described here. Although significant researches were carried out in the second half of 1990’s, still there were many twists and turns before an
Technical Library | 2015-12-23 16:57:27.0
The onset of copper barrel cracks is typically induced by the presence of manufacturing defects. In the absence of discernible manufacturing defects, the causes of copper barrel cracks in printed circuit board (PCB) plated through holes is not well understood. Accordingly, there is a need to determine what affects the onset of barrel cracks and then control those causes to mitigate their initiation.The objective of this research is to conduct a design of experiment (DOE) to determine if there is a relationship between PCB fabrication processes and the prevalence of fine barrel cracks. The test vehicle used will be a 16-layer epoxy-based PCB that has two different sized plated through holes as well as buried vias.
Technical Library | 1999-05-07 10:13:38.0
This paper will review the device physics governing the operation of the industry standard ETOX™ flash memory cell and show how it is ideally suited for multiple bit per cell storage, through its storage of electrons on an electrically isolated floating gate and through its direct access to the memory cell.
Technical Library | 2019-11-07 08:59:14.0
Inductors realized with high permeable MnZn ferrite require, unlike iron-powder cores with an inherent dis-tributed gap, a discrete air gap in the magnetic circuit to prevent saturation of the core material and/or tune the inductance value. This large discrete gap can be divided into several partial gaps in order to reduce the air gap stray field and consequently the proximity losses in the winding. The multi-gap core, realized by stacking several thin ferrite plates and inserting a non-magnetic spacer material between the plates, however, exhibits a substan-tial increase in core losses which cannot be explained from the intrinsic properties of the ferrite. In this paper, a comprehensive overview of the scientific literature regarding machining induced core losses in ferrite, dating back to the early 1970s, is provided which suggests that the observed excess core losses could be attributed to a deterioration of ferrite properties in the surface layer of the plates caused by mechanical stress exerted during machining.
Technical Library | 2019-10-10 00:26:28.0
Voids are a plague to our electronics and must be eliminated! Over the last few years we have studied voiding in solder joints and published three technical papers on methods to "Fill the Void." This paper is part four of this series. The focus of this work is to mitigate voids for via in pad circuit board designs. Via holes in Quad Flat No-Lead (QFN) thermal pads create voiding issues. Gasses can come out of via holes and rise into the solder joint creating voids. Solder can also flow down into the via holes creating gaps in the solder joint. One method of preventing this is via plugging. Via holes can be plugged, capped, or left open. These via plugging options were compared and contrasted to each other with respect to voiding. Another method of minimizing voiding is through solder paste stencil design. Solder paste can be printed around the via holes with gas escape routes. This prevents gasses from via holes from being trapped in the solder joint. Several stencil designs were tested and voiding performance compared and contrasted. In many cases voiding will be reduced only if a combination of mitigation strategies are used. Recommendations for combinations of via hole plugging and stencil design are given. The aim of this paper is to help the reader to "Fill the Void."