The aerospace and defense (A&D) industry offers unique challenges for developers due to the incredibly stringent set of rules and regulations these products must pass under. Creating complex PCBs in the A&D industry will always mean multiple spins in order to develop a reliable and cost-effective design. But in reality, most A&D companies don’t have the time or money to do more than a few board re-spins.
In exploring the drivers for improving PCB design in the A&D industry, we found that market demand for lower cost products was listed as the top pressure. A&D companies were 14% more likely to say lower cost demands were their major challenge than companies outside of the industry. Second on that list, and indicative of the need to minimize design rework, was the demand for more reliable products. Aerospace and defense companies were 44% more likely to list reliability as their top pressure versus companies not in aerospace or defense to improve PCB design.
Developers need simulation and virtual prototyping to test their designs in an environment that saves cost and time while avoiding excessive respins. It is essentially collecting key inputs from the electrical or physical design processes and testing these features against assumptions and constraints made for the overall design. During this stage, development and optimization of constraints are performed to account for all known variations affecting design performance. This process allows for designers to correct a design early in the cycle to ensure the board is properly constructed.
In terms of construction, signal integrity is one of the highest concerns for PCB designers. The signal must remain stable throughout the entire transmission path from component to component, especially along the power distribution network and the integrated circuit (IC) logic paths. For example, one engineer designed a board where the input signal to a DRAM controller was ringing back and crossing the threshold again. This was problematic since re-crossing the threshold would flip the bit and most likely cause the design to fail. Changes were made to the transmission line impedance from 50 Ohm to 35 Ohm, along with additional adjustments to the input termination and controller impedance, as well as a slower output configuration for the controller, which greatly reduced the ringing.
These modifications would have been impossible to do under manual prototyping as finding the cause of an issue such as ringing would have been very difficult with just measurements alone. Therefore, potentially hours of bench time could have been lost tracking down the issue. A&D companies prevent this potential error from occurring by performing simulations. They are 12% more likely than non-A&D companies to use signal integrity analysis, and 17% more likely than non-A&D to use analog, digital, or RF simulations.
For complex A&D designs, it’s important for developers to have the ability to virtually model and analyze their designs prior to fabrication. Giving users the ability to simulate designs helps improve efficiency and increase productivity. For more on this subject, check out the full report.