Quicker and smarter

In the ever-changing world of avionics, today's humble PCB contains a host of electronics devices - all of which are gradually becoming much smaller, smarter or both.

This means board designers are not only faced with size constraints, but also the pressure to complete their designs quicker than ever. If that wasn't enough, with other developments that affect board design increasingly being performed in parallel, changes in one area of the board could have a major impact on the work of other design teams that are often spread globally.
To avoid major headaches, help is on hand as a host of electronic design automation (EDA) developers provide solutions to help layout designers overcome the hurdles of getting product to market.

According to Mentor Graphics' director of market development, Systems Design Division, John Isaac, the basic business drivers are becoming more common throughout all of the electronics industries: “How can I get the most competitive product to market faster at the lowest development and manufacturing cost? In other words, do more, faster, with less. This is especially important in today's recession market where there is less money being spent on their products. In addition, companies are also faced with organisational challenges. They may have members of their design teams spread around the world or they may be outsourcing their manufacturing. Mentor recognises these business drivers and has gone beyond normal PCB design-centric software to look at the entire product development process.”

The same demands can be applied to the technology, such as increasing integration into a smaller footprint, thermal management issues and designing in the latest testing methodologies. Zuken's principal applications engineer, Andy Buja and senior applications engineer, Ed Duranty say customers require solutions that comprise a single software tool to encompass all aspects of the latest technical and testing requirements, as well as prospective future requirement needs.

“We're seeing the need to integrate current packaging sizes into smaller ones due to weight constraints and smaller enclosure considerations. Designing PCBs with various fabrication, packaging, constraint issues, and testing requirements present challenges for the entire design team and is a concurrent process. The methodology being adopted is becoming known as ‘right the first time' and includes pre-layout and concurrent analysis in both single- and multi-board designs. Customers realise that designing for signal integrity reasons doesn't favour well with time to market initiatives if they cannot test the entire design in a single application. We address these requirements within our software tools and the customers are seeing the benefits by utilising the process methods.”

According to Altium's product manager, Rob Irwin, weight is everything on an aircraft. “American Airlines don't paint their MD80s because it saves over 200lbs of weight,” he claims. “With electronic production materials, weight and size are almost proportional, whilst space in an aircraft is a premium commodity. 3D modelling of the electronics is the key. For example, most avionics assemblies involve multiple boards in a ‘clam shell'. The mechanical assembly of these systems can be made faster with good 3D modelling. Altium Designer is the only system that lets board designers link directly to mechanical enclosure models and manipulate them in the PCB design environment. This helps guarantee perfect fit between the case and the PCB before the board is manufactured, allowing complex assemblies to be tested in the design stage and eliminate the need for multiple design spins.”

The issue of reducing design spins can be applied to board components too, as designers look to overcome the problems of enforced design changes when board developments are performed concurrently with other components.

“Working openly and transparently is vital when urgent design changes require companies to respond quickly using core capability and previous experience,” explains Quantum CAD's senior project manager Carl O'Roche. “Collaborating on all aspects of product development ensures the correct data is available to the right people, to make the right decision, at the right time. We use the e-collaboration platform CXInsight to integrate the CEM and OEM into a single working environment to solve collaboration issues, ensuring all parties are working on the same data set through each step in the product lifecycle. If the post product introduction stage is not considered early, no amount of manufacturing expertise or effort will get quality and manufacturability into the final product.”

More for less

One dominant avionics trend involves the effects of the More Electric Aircraft (MEA) philosophy. This requires designers to understand how it will impact their businesses and how they can maximise this opportunity.

“We've seen old systems replaced by newer ones based on digital signal processing (DSP) rather than analogue signals, to extend the life of an aircraft,” notes Irwin. “Altium's design tool promotes creative thinking as well as good design practices, such as using version control and providing a live design environment that allows engineers to test an idea in real hardware and then document it to show evidence of their design behaving according to spec. This capability is still largely untapped in aerospace but we expect it to be utilised more over time.”

The flow of analogue to digital systems and the increasing use of ‘intelligent' components could spell the end for the traditional PCB. Will it still have a role to play in the aircraft of tomorrow?
“Since I joined the business, someone has always said the PCB would soon be replaced by a single component,” claims Issac. “The PCB and the software is where a company adds value, and except for those companies with the time and money to design custom ASICs, everyone has access to the same set of ICs and FPGAs. It is how you put them together on the PCB that makes a more competitive product.”

O'Roche adds that the need for a carrier means there will always be a need for the PCB: “There's the possibility that the PCB might take another form, but it will always be needed. The Adept-SiP project is a great example of how we're making electronics smaller, quicker and faster to market. It shows we're looking to store more inside the board to free up space, allowing for greater functionality.”

Zuken's Buja and Duranty say traditional PCB technologies will never disappear: “It will continue to evolve as the rise of new breakthroughs in ‘intelligent' components continues. Components will still need a ‘base' to communicate through whether it is rigid, flex, rigid/flex, or another type of PCB technology.”

The last word goes to Irwin: “PCBs are a reliable, well-understood technology, making it difficult to depart from the technology for an industry with so many regulations and constraints. However, PCBs are heavy and bulky, so when newer, denser technology matures to a point where it's generally accepted as safe, it will be used in avionics. The first step from analogue to digital has already taken place. The next, using large capacity FPGAs to consolidate system functionality, started as a trickle, but is gaining momentum and will eventually replace discrete microprocessor-based systems. This will allow component counts on PCBs to decrease, meaning more compact and power-efficient designs. However, for the foreseeable future, there will still be a PCB underpinning it all.”

www.zuken.com
www.altium.com
www.quantumcad.co.uk
www.mentor.com