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Carlsbad, CA, United States

Gao C.,Molex Inc. | Patel P.,Lenovo
2015 IEEE 24th Conference on Electrical Performance of Electronic Packaging and Systems, EPEPS 2015 | Year: 2015

For high speed interconnect design, trace crosstalk due to trace mis-registration can be as high as connector and vias. One should make sure such crosstalk is well managed. This paper presents the parametric study on trace crosstalk with respect to the mis-registration margin and provides some guidelines in practical system designs. © 2015 IEEE. Source

Dunham D.,Molex Inc. | Lee J.,Molex Inc. | McMorrow S.,Teraspeed Consulting Group | Shlepnev Y.,Simberian Inc.
DesignCon 2011 | Year: 2011

With Data rates climbing to 10-12.5 Gb/s and plans for 28 Gb/s, it becomes important to increase PCB test fixture bandwidth from the typical 20 GHz to 50 GHz. There are several vendor Vector Network Analyzers that will sweep this high, but not many PCB launch connectors that can accurately launch these high frequencies. This paper will: •Present modeling and validate data for a novel compression launch 2.4mm coaxial connector, functional up to 50GHz •Show methods for analytical modeling and measurements for optimizing the PCB launch and escape under the 2.4 mm connector •Demonstrate accurate broadband material characterization, using the method of generalized modal S-parameters, out to 50 GHz The 2.4mm design includes a compression attach center conductor that does not require a solder attach to the PCB. The 2.4mm coax design meets all the standard 2.4mm mechanical interface standards, with a VSWR of < 1.2 @ 50 GHz using back-to-back connector attachment. This paper will review EDA analytic modeling methodology and results for the integrated 2.4mm coaxial connector with several PCB layout designs. The final optimized PCB design was fabricated, measured and correlated to the analytical model. Source

Huang X.,University of Houston | Zheng J.,University of Houston | Chen J.,University of Houston | Wu X.,Molex Inc. | And 3 more authors.
IEEE International Symposium on Electromagnetic Compatibility | Year: 2014

Using absorption materials to reduce RF heating during MRI procedure is studied in this paper. Materials with different electromagnetic absorption characteristics are used to alter the EM and current distributions on the device. Consequently, the RF induced heating behaviors of external fixation devices can be reduced. Numerical and experimental studies are provided to demonstrate the potentials of reducing the RF heating for external fixation devices of using lossy materials. © 2014 IEEE. Source

Amleshi P.,Molex Inc. | Gao C.,Molex Inc. | Correia D.,Molex Inc. | Shen L.,Insieme Networks Inc.
DesignCon 2014: Where the Chip Meets the Board | Year: 2014

In current high-speed (25Gbps+) backplane systems, a few picoseconds (ps) of intra-pair skew can degrade the signal quality; therefore, to maintain a high quality digital data transmission, it is of prime importance to identify and minimize the sources of skew. Skew values from trace bend, backplane connector, and chip package are usually known or could be determined; therefore, their overall skew at the receiver can be compensated through trace equalization techniques. However, skew generated from the variations in the effective dielectric constant of PCB material could not be easily predicted during the design and cannot be compensated. In this study, we characterize the transmission quality of a simple link of known length as a function of the magnitude of such "unaccounted" skew and investigate possible techniques to reduce its effects. Source

Amleshi P.,Molex Inc. | Gao C.,Molex Inc.
IEEE International Symposium on Electromagnetic Compatibility | Year: 2014

At 25Gbps and beyond, crosstalk noise can degrade a backplane channel signal quality significantly. High density interconnects can generate high crosstalk noise due to the close proximities of the components. In particular, interfacing dense chips and connectors with PCB requires dense implementation of signal via structures. Placing ground via guards can reduce the field overlap between signal via structures but this would also reduce density and create impedance discontinuities; therefore, these guarding via structures need to be placed strategically to reduce their adverse effects. In this study we analyze how near and far end crosstalk (NEXT and FEXT) within the signal via fields are affected by anti-pad, ground via, and ground plane layers. It will be shown that FEXT and NEXT can be affected differently in the presence of ground plane anti-pads. Relationships between these parameters with respect to ground anti-pads and the effectiveness of guarding via structures in reducing crosstalk will be presented. © 2014 IEEE. Source

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