Demanding Application

The study supported the design of a PCB for an automotive application in a Japanese market.  The device consisted of a number of components connected to a PCB via BGA.

The study comprised two major elements:

• Review of requirements
• Structural integrity assessment

Understanding

The review looked at the environmental vibration, shock and thermal shock requirements placed on the PCB.  The requirements were based on a standard produced by the Electronic Industries Association of Japan.  A comparison was made with similar British Standards and US Military Standards.

The mechanical requirements were therefore extracted and clearly traced back to source standards.  This allowed our client to make an informed and realistic commercial agreement with their client.

Structural Analysis

The second part of the study was to perform a structural integrity assessment of their initial design to determine the likelihood of passing the various tests.  The assessment concentrated on the bending strength of the actual board and the connection between the components and the PCB.  It was found that the main ASIC, connected to a daughter board by a peripheral BGA assembly, would not meet the shock standard.

 
Design Changes

Some design changes to the daughter to main board connections and the BGA assembly method were then tested, and found to alleviate the problem.

 
Risk Reduction

Crucially, this study was conducted at the very start of the design process and was able to resolve this issue before most of the electronic design had even begun.