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established to investigate the drop impact response. A board level drop impact model, i.e., the novel input-Dynamic perfondurind impctr is areat acceleration model, is also developed. Modal analysis is concern to semiconductor and electronic product codce'ytefnteeeetmto.Md conducted by the finite element method. Mode mamufacturers, especially for portable devices such as .. moblie phones. In this paper, the drop impact response of sproiinmto ste dpe ofn h yai moblie phne..nhippe,hedrpm e . o responses subjected to an impact load. Parameter studies a mobile phone is investigated by an analytical dynamics have been done on the basis of performed analysis. Then, model. In order to capture some most important affected .. . . g we have developed engineering guidelines for the factors, we decouple this problem to be a two-step preliminary selection of the geometries and materials of analysis. First, finite element analysis is used to determine PCBs, and the stiffness of housings, so that the dynamic the effective stiffness for housing and PCB board . lti stability is maintained. Finally, the developed models are respectively. Second, a two-degree-of-freedom analyical applied to evaluate the dynamic response of a dynamic model is developed to investigate the drop commercially used cellular phone.impact response. Such an approach allows parametric analysis to determine the important design parameters, 2. Analytical Model which are important to the preliminary selection of Many mobile phones are composed of a PCB board geometries and materials of PCB boards and stiffness of with packages amounted on it, and a plastic housing to housings so that the dynamic stability is maintained. hold the PCB board. The mobile phone can be simplified Board level finite element analysis is also performed as a two-degree-of-freedom system, as shown in Fig. 1. using input-acceleration model. The results are in good ml and k1 are mass and spring constant of PCB board; m2 agreement with the analytical model results developed and k2 are mass and spring constant of housing. xl and x2 above. Finally, both methods are applied to evaluate the are displacements for PCB and housing, respectively. dynamic response of a commercially used cellular phone.