• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.3
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• pp.176-183
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• 2015

This research proposes a method to estimate the fatigue life of SSD(solid-state drive) due to the effect of dummy solder ball under forced vibration. A finite element model of the SSD was developed to simulate the forced vibration and a modal testing was performed to verify the developed finite element model. Fatigue life of the SSD under vibration was experimentally determined according to JEDEC standard in which the SSD was excited by a sinusoidal sweep vibration within the narrow frequency band around the first natural frequency until the SSD fails. Basquin's equation was introduced to estimate the fatigue life of the SSD due to the effect of dummy solder balls. It shows that the dummy solder balls are effective elements of the SSD to increase the fatigue life of an SSD by increasing 700 times of the fatigue life of the given SSD.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.408-416
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• 2010

A dumbbell-type CPW transmission-line structure has been proposed to improve the return loss of the transmission line between a driver IC and flip-chip-bonding VCSEL(Vertical Cavity Surface Emitting Laser) in a hybrid opto-electric circuit board(OECB). The proposed structure used a pair of dummy ground solder balls on the ground lines for flip-chip bonding of the VCSEL and designed the dumbbell-type CPW transmission line to improve reflection characteristics. The simulated results revealed that the return loss of the dumbbell-type CPW transmission line was 13-dB lower than the conventional CPW transmission line. A 4-dB improvement in the return loss was obtained using the dummy ground solder balls on the ground lines. The variation rate of the reflection characteristic with the variation of terminal impedances of the transmission line (at the output terminal of the driver IC and the input terminal of the VCSEL) is about ${\pm}2.5\;dB$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.978-983
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• 2014

This research proposes a method to estimate the fatigue life of solid-state drive(SSD) due to the effect of dummy solder ball under forced vibration. Mechanical jig is developed to describe the SSD in laptop computer. The jig with SSD is mounted on a shaker, and excited by a sinusoidal sweep vibration within the narrow frequency band around the first resonant frequency until the SSD fails. A finite element model of SSD is also developed to simulate the forced vibration. It shows that the solder joints at the corners of controller package are most vulnerable components and that placing dummy solder balls at those area is effective method to increase fatigue life of SSD.