Maintaining reliability
Reliability is one of the key issues that designers face when creating a PCB for a transportation product. Cars and trucks are expected to withstand extreme temperatures and rigorous conditions throughout their lifecycle; and this includes the printed circuited boards and components used in the design. It is no secret that the automotive industry has faced this challenge for many years; but by adding more electronic modules, selecting the right materials and components becomes even more important. Choosing between a low-temperature, co-fired ceramic and a high-temperature FR-4 could mean the difference of a few cents or more for each PCB in the system. Taking into account the number of cars one company manufactures in a year, those few pennies can have a significant impact on the overall margin of each vehicle.
Fig. 1: Upfront system planning in a single environment addresses multiple engineering disciplines. For full resolution click here .
Reliability is also tied to the issue of the wide array of the latest features and interfaces that come with cars today. Most cars have optional navigation systems, portable music interfaces, and Bluetooth hands-free systems to choose from, and all of these options introduce a new set of concerns during product development: signal integrity, analog simulation, RF analysis, and EMC studies are becoming an integral part of the design process. What makes the problems unique for automotive engineers is that in addition to dealing with the range of power supplies introduced into the PCB that is typically seen in consumer products, they are also working with other large voltage and current supplies throughout the system of the car to make it operational.
With these elements in mind, ensuring that signal quality and cross talk interference are maintained within specifications is essential. Throw in the fact that some cars include memory and SuperSpeed USB, and engineers are now dealing with constraint management issues along with the need to conduct