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|Drop Impact Dynamic Response Study of JEDEC JESD22-B111 Test Board|
|Keywords: Drop test, Data acquisition cable, Dynamic response|
|Mobile and handheld electronic devices are prone to being dropped. This drop event may result in failure of solder joints inside these devices. The need for RoHS compliant boards coupled with the demand for reliable electronics has spurred the creation of the JEDEC Standard JESD22-B111 to standardize the method of drop testing surface mount electronic components. However, there has been little study on the effects of the additional mass a data acquisition cable creates on the board and rigidity of components on drop test reliability. This paper examines the drop impact dynamic responses of the JEDEC JESD22-B111 board. Of interest are the effects of an attached cable and edge-bond materials on the maximum acceleration at different component locations. In this study, the JESD22-B111 compliance test board was used. Fifteen 0.5mm pitch CSPs were assembled on the board using Sn3.0Ag0.5Cu lead free solder. The drop test was conducted using a Lansmont M23 TTSII Shock Test system. A half-sine shock impact pulse was applied to the JESD22-B111 compliance test vehicle with 900G, 1500G, and 2700G; with 0.7ms, 0.5ms, and 0.3ms durations, respectively. Two accelerometers were used to monitor the maximum acceleration with one placed on the drop table and the other on the board component. Statistical analysis was used to determine the effects of different edge bond materials and a cable on the maximum acceleration at individual component locations. Results show that the maximum acceleration differs significantly at different component locations and the peak acceleration at some component locations are much higher than on the drop table. A correlation between the maximum acceleration and the number of drops until component failure was assessed. This paper also calculated the expected deflection of the test board under different G-level, and the results were in agreement with the deflection measured with a high-speed camera.|
|Michael Krist, Student
Cal Poly State University
San Luis Obispo, CA