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 | 2015-05-28 17:34:48.0
The printed circuit board assembly industry has long embraced the "Smaller, Lighter, Faster" mantra for electronic devices, especially in our ubiquitous mobile devices. As manufacturers increase smart phone functionality and capability, designers must adopt smaller components to facilitate high-density packaging. Measuring over 40% smaller than today's 0402M (0.4mmx0.2mm) microchip, the new 03015M (0.3mm×0.15mm) microchip epitomizes the bleeding-edge of surface mount component miniaturization. This presentation will explore board and component trends, and then delve into three critical areas for successful 03015M adoption: placement equipment, assembly materials, and process controls. Beyond machine requirements, the importance of taping specifications, component shape, solder fillet, spacing gap, and stencil design are explored. We will also examine how Adaptive Process Control can increase production yields and reduce defects by placing components to solder position rather than pad. Understanding the process considerations for 03015M component mounting today will help designers and manufacturers transition to successful placement tomorrow.
Technical Library | 2017-06-22 17:11:53.0
C-mode scanning acoustic microscopy (C-SAM) is a non-destructive inspection technique showing the internal features of a specimen by ultrasound. The C-SAM is the preferred method for finding “air gaps” such as delamination, cracks, voids, and porosity. This paper presents evaluations performed on various advanced packages/assemblies especially flip-chip die version of ball grid array/column grid array (BGA/CGA) using C-SAM equipment. For comparison, representative x-ray images of the assemblies were also gathered to show key defect detection features of the two non-destructive techniques.
Technical Library | 2012-12-26 20:18:50.0
①Single side The basic flexible printed circuit board is used of substrate of single side pcb materials and coated coverlay after finishing printed. ②Double sided That is made of substrates of double sided printed circuit board with double surface coated coverlays after finishing printed. ③Single copper foil with double coverlays Single copper foil coated different coverlays with double surface after finishing printed. ④Air gap Laminating two single printed circuit board together with no glue and bare design to meet high flexibility requirements. ⑤Multilayer That is designed for three and above circuit layers by laminating single side printed circuit board or double sided printed circuit board. ⑥COF IC chips and electronic components are installed on the flexible circuit board directly. ⑦Rigid-Flexible PCB Combined to rigid PCB with supporting and flexible PCB with high flexibility.
| 1 |
