Symmetry degradation of differential circuits induced by uneven gold plating of high‐speed connectors in extreme environment

2020 ◽  
Vol 62 (12) ◽  
pp. 3716-3726
Author(s):  
Ziren Wang ◽  
Jinchun Gao ◽  
Puxuan Tian ◽  
Gang Xie
Keyword(s):  
High Speed ◽  
Extreme Environment ◽  
Gold Plating ◽  
Differential Circuits

Comparative Evaluation of MoS2 and WS2 as Powder Lubricants in High Speed, Multi-Pad Journal Bearings

1999 ◽  
Vol 121 (3) ◽  
pp. 625-630 ◽  
Author(s):  
C. Fred Higgs ◽  
Crystal A. Heshmat ◽  
Hooshang Heshmat
Keyword(s):  
Comparative Evaluation ◽  
High Speed ◽  
Solid Lubricants ◽  
Extreme Environment ◽  
Journal Bearings ◽  
Lubricating Film ◽  
Constant Friction ◽  
Traction Coefficient ◽  
Limiting Value ◽  
Selection Of

As part of a program to develop solid/powder-lubricated journal bearings, a comparative evaluation has been performed to aid in determining whether MoS2 and WS2 powder are suitable lubricants for high-speed, extreme-environment multi-pad journal bearings. Plots of traction coefficients, friction, frictional power loss, and bearing pad temperature are presented as a means for comparing various powder lubricants. This paper primarily focuses on experiments carried out on a three-pad journal bearing and a disk-on-disk tribometer. Results showed that MoS2 traction curves resemble that of SAE 10 synthetic oil. Unlike liquid lubricants, powder films have a limiting shear strength property. Once the powder reaches this limiting value, the maximum traction coefficient is limited and the powder essentially shears along sliding walls. Experimental traction data shows evidence of this property in various powders. The thermal performance of the bearing was evaluated at speeds up to 30,000 rpm and loads up to 236 N. Although WS2 displayed constant friction coefficient and low temperature with increasing dimensionless load, MoS2 exhibited frictional behavior resembling that of a hydrodynamic lubricating film. In this paper, an attempt has been made to provide a criterion for the selection of solid lubricants for use in those tribosystems that may be operated in a high speed/load regime (i.e., high strain rates) as an alternative yard stick to conventional comparative approaches.

High Temperature Silicon Carbide Power Modules for High Performance Systems

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000159-000166 ◽  
Author(s):  
J. Hornberger ◽  
B. McPherson ◽  
J. Bourne ◽  
R. Shaw ◽  
E. Cilio ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
Extreme Environment ◽  
High Energy ◽  
Energy Applications ◽  
Power Modules ◽  
Reliability Systems

The demands of modern high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon-based semiconductors. The advantages of silicon carbide (SiC) are well known, including high temperature operation, high voltage blocking capability, high speed switching, and high energy efficiency. In this discussion, APEI, Inc. presents two newly developed high performance SiC power modules for extreme environment systems and applications. These power modules are rated to 1200V, are operational at currents greater than 100A, can perform at temperatures in excess of 250 °C, and are designed to house various SiC devices, including MOSFETs, JFETs, or BJTs. One newly developed module is designed for high performance, ultra-high reliability systems such as aircraft and spacecraft, and features a hermetically sealed package with a ring seal technology capable of sustaining temperatures in excess of 400°C. The second module is designed for high performance commercial and industrial systems such as hybrid electric vehicles or renewable energy applications, implements a novel ultra-low parasitic packaging approach that enables high switching frequencies in excess of 100 kHz, and weighs in at just over 130 grams (offering ~5× mass reduction and ~3× size reduction in comparison with industry standard power brick packaging technology). It is configurable as either a half or full bridge converter. In this discussion, APEI, Inc. introduces these products and presents practical testing of each.

High Temperature Silicon Carbide Power Modules for High Performance Systems

2012 ◽  
Vol 717-720 ◽  
pp. 1219-1224 ◽  
Author(s):  
Alexander B. Lostetter ◽  
J. Hornberger ◽  
B. McPherson ◽  
J. Bourne ◽  
R. Shaw ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
High Speed ◽  
High Performance ◽  
Extreme Environment ◽  
High Energy ◽  
Power Modules ◽  
High Performance Systems ◽  
Silicon Based ◽  
High Speed Switching

The demands of modern high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon-based semiconductors. The advantages of silicon carbide (SiC) are well known, including high temperature operation, high voltage blocking capability, high speed switching, and high energy efficiency. In this discussion, APEI, Inc. presents two newly developed high performance SiC power modules for extreme environment systems and applications. These power modules are rated to 1200V, are operational at currents greater than 100A, can perform at temperatures in excess of 250 °C, and are designed to house various SiC devices, including MOSFETs, JFETs, or BJTs.

scholarly journals Bearings for Vacuum Operation—Retainer Material and Design

1963 ◽  
Vol 85 (2) ◽  
pp. 129-134
Author(s):  
Harold E. Evans ◽  
Thomas W. Flatley
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Vacuum System ◽  
Pure Gold ◽  
External Loading ◽  
Motor Speed ◽  
Gold Plating ◽  
Bearing Life ◽  
Bearing Failures ◽  
Film Lubrication

This report describes the initial phase of an investigation of the high-speed operation of miniature ball bearings, with metallic film lubrication, in a vacuum environment. Phase I of this study was conducted to determine the most promising retainer material and design for use in a general study of the effectiveness of various metallic coatings as lubricants. Fully machined retainers of five different materials, with all balls and races of gold plated 440C stainless steel, were tested. Both pure gold plating and gold with additives were investigated. Size R2-5 bearings were run without external loading at a nominal motor speed of 10,000 rpm and the goal is a bearing life of 1000 hours in an ambient pressure of 10−7 torr. The results show that: (1) Thin metallic films as lubricants show real promise when used in a vacuum environment; (2) pure gold plating is not as effective as the plating with additives; (3) fully machined retainers provide good performance, and the use of relatively hard retainer materials significantly extends the useful life of the bearings; and (4) the bearing failures tended to be catastrophic rather than gradual, making the prediction of the onset of failure difficult. A special multiport oil-free vacuum system designed and built for this program proved extremely effective in achieving a vacuum of 10−7 torr, and in permitting the operation of seven individual tests at one time.

scholarly journals High speed selective gold plating of lead frames

Gold Bulletin ◽  
1976 ◽  
Vol 9 (2) ◽  
pp. 45-45
Author(s):  
Keyword(s):  
High Speed ◽  
Gold Plating

Advanced Devices and Electronic Packaging for Harsh Environment

2013 ◽  
Vol 2013 (1) ◽  
pp. 000937-000950
Author(s):  
Aicha Elshabini ◽  
Fred Barlow ◽  
Sharmin Islam ◽  
Pin-Jen Wang
Keyword(s):  
Electronic Packaging ◽  
High Speed ◽  
Schottky Diodes ◽  
Extreme Environment ◽  
Harsh Environment ◽  
Reliability Testing ◽  
Power Devices ◽  
Low Loss ◽  
Die Attach ◽  
Selection Of

The paper addresses the challenges in electronic packaging for extreme environment based on experimental work of the researchers and conducted reliability testing to evaluate high speed devices suitable for these applications, substrates, die attach, wire bonding, and encapsulation and housing. In particular, the researcher's work has focused on SiC power devices with low loss high voltage Schottky diodes with significant applications, high temperature JFETs and SiC MOSFETs (double trench), and GaN microwave devices. The paper provides recommendations for selection of devices, substrates, die attach, and encapsulation and housing for these applications.

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