There is general consensus amongst Australia’s PCB designers that, at the high end of the spectrum at least, their job is getting more complex. Senior PCB Engineer and Team Leader of Blackmagic Design, Roger Hughes, cites increasing signal frequencies, sharp edge rates and complex routing topologies as some of the issues he faces.
“We have far more constraints on routing [in order] to meet signal integrity, impedance and timing requirements etc,” Hughes told Electronics News. “And power architecture/thermal management is now a big issue and general component size reduction and in particular CSP [chip scale packaging] has led to greater use of HDI [high density interconnects].”
And these challenges must be navigated even as costs are cut, increased competition demands greater product differentiation, and market windows shrink.
Moreover, in recent years, the role and responsibilities of PCB designers have expanded, requiring active collaboration with the mechanical designers and increased transparency in providing verification and documentation to clients.
But the march of technology has also provided designers with more powerful tools with which to tackle these challenges. Gone are the days of light tables, paper and tape. PCB designers now have to get their heads around rapid advances in electronic design automation (EDA) software, unparalleled collaboration and connectivity features, reusability, simulation and an unprecedented visibility into the role of PCB design in the overall product development process.
So how are Australia’s PCB design teams faring?
Denser, faster, hotter
Grant King, application engineer at EDA vendor Mentor Technologies, sympathises with Roger Hughes, adding that considerations of trace impedance, signal velocity and timing are now standard in most modern designs.
“[It’s] the designer’s responsibility to [meet the specification and be conscious that] manufacturing tolerances including trace width, dielectric thicknesses and constants will have an impact on [these considerations],” says King. “These are factors which designers must understand, control and specify to achieve the desired goal.”
But for King, thermal considerations are the key factor as devices become smaller and more sophisticated.
“Turn every feature of a cell phone on and crank the transmitter up to medium to full power and it will get very hot,” he explains.
King suggests contemporary designs don’t have the best thermal characteristics and rely on the power of EDA to ensure they can handle the heat.
“Conduction of energy from the transistor junctions through the component cases, then through polymers with normally poor thermal characteristics, is the main mode of heat transfer to the outside world.
“Computational fluid dynamics and thermal modelling is the only way to make sure the board will work when assembled in its housing along with other devices guaranteed to radiate heat and influence airflow,” King explains.
The increased density of board designs means thousands of closely packed holes in most layers of a PCB. According to King, failures in the structure of the PCB cause additional internal heating and can be buried many layers down - making the fault difficult to debug.
“At best, voltage fluctuations to supply pins may be observed but worst case scenarios include internal and external heating problems, trace delamination and even supply fusing,” he notes.
Mentor Graphics' FloTHERM provides detailed descriptins of the layer stack-up and metallic distribution to accurately predict conductive heat flow within the PCB substrate
Yet the same advance of technology that’s increased the complexity of PCBs has also yielded the design tools that help reduce costs, and improve the designer’s efficiency.
EDA software from Altium and Mentor Graphics’ HyperLynx can perform virtual tests, simulations and analysis of factors like signal integrity, interference checking, thermal performance and power integrity before proceeding to prototyping stages.
By using the software to simulate performance and virtually prototype PCBs and devices, it’s possible to reduce the costs of multiple prototype turns, improve certainty, and accelerate product development.
Reduce, reuse, retool
Steven Murray, manager of Sydney-based Airborn Electronics, says component advances have also played a part in making PCB designers’ jobs easier.
According to Murray, digital noise on power supplies used to be a big problem, but the development of low equivalent series resistance (ESR) capacitors and multilayer boards have eased the problem.
“Power supply distribution and multiple voltages were always an issue. But now we can just drop in a ready made DC-to-DC converter, and the job is done,” says Murray. “Tricky analogue inputs can now be handled by ready-made chips for thermocouple input, high side current measurement, acceleration, radio, GSM, compass modules – everything is done for you; as a designer we just need to connect [the components].”
These off-the-shelf components allow simple reuse of large elements of older designs. Mentor Technologies’ Grant King says this means a designer can ‘drop in’ a known good chunk of circuit into a new design with rules, traces and placement intact.
The ability to reuse previous intellectual property (IP) from reference designs and design blocks is something Altium manager Dr Marty Hauff says his company encourages. Altium is advocating that common design blocks are ‘captured’ in a reusable format to be shared by all designers.
EDA solutions like Altium Designer now merge multiple other domains of product development with traditional PCB design
“This allows designers to rapidly build new systems with advanced functionality,” Dr Hauff told Electronics News. “But more importantly, it frees designers to add value in other areas of the product and ensure better product differentiation.”
King says design reuse, while helped by software, is also dependent on good design discipline. For example, designers should plan for reuse by constraining the module’s form factor to be compatible with future products.
Designers should also document all critical features and constraints of the module to avoid changes which compromise its integrity.
Increased connectedness across the globe is an advantage to PCB designers because it not only allows IP to be shared, but also enables work on a single project to be allocated to several engineers. In multinational companies, a project may involve designers on different continents, making one designer’s bedtime another’s workday.
Such practises can be highly confusing, especially if adherence to version control is lax, and designers fail to properly communicate changes to one another.
But King notes that software and connectivity advances have made cross-border, cross-time zone collaboration much more controllable.
“A more robust methodology has recently emerged where a host design can be shared across the world such that many remote teams can edit the design in real time without the nightmare of manual manipulation of transferred databases,” he explains. “This not only compresses the layout phase, but enables an engineering organisation in a country like Australia - with high employment costs - to utilise lower cost layout services while maintaining absolute control of the design.”
With today’s streamlined workforce, control of that design has to encompass more than just the PCB. That’s why EDA software companies like Altium are pushing for a more holistic approach to product design.
“Given that companies make their money from completed products rather than PCBs, our focus extends beyond the design of fully functional PCBs to ensure that the products that those PCBs go into are also successful,” says Dr Hauff.
For this reason, Altium is aiming to improve designers’ visibility of the electronic supply chain. With many component manufacturers and vendors putting advanced specifications and supply chain information online, Altium believes designers can make better decisions in component selection by having access, within their EDA software, to factors like the price and availability of critical components.
A holistic approach inevitably demands a merging of EDA and mechanical CAD (MCAD) design processes. This is becoming particularly evident in the higher end sectors involving handheld and mobile devices, where there is increasing need to ensure PCB designs can squeeze into shrinking form factors.
“Faced with the added challenge of making products that are both functionally and aesthetically appealing, EDA and MCAD design processes must converge,” Dr Hauff says. “The design of the PCB, including the selection and location of connectors and user interface components, is as much an MCAD challenge as it is an EDA one.”
In order for such a convergence to be successful, EDA and MCAD design teams also need to overturn the conservative design culture within an organisation. According to Dr Hauff, designers, be they electronic or mechanical, will need to assume greater individual ownership over the complete product rather than just their specialised segments of the design flow.
Back to basics
However, not all PCB designers agree with the need to integrate EDA and MCAD. While acknowledging that there is demand for such integration, Doug Ford, owner of Doug Ford Analogue Design, is a vocal opponent of the push for what he considers overpriced, ‘bling-loaded’ software.
“Software vendors … are trying to force a change in methodology instead of producing CAD software which aligns better with our existing methodology,” Ford told Electronics News. “They are trying to sell software which is capable of doing too much, and charging too much for the privilege.”
For Ford, over-dependence on software capabilities (notably, auto-routing) can lead to designers not learning the skills that their forebears relied on.
“This all boils down to how experienced you are, how experienced you want to be, and how much of the responsibility you want to delegate to the CAD package, instead of taking responsibility for [the design] yourself,” Ford says.
Not all designers need high-end design capability. While some are working on next generation smart phone with capabilities akin to that of supercomputers from the 90s, others are rework existing mid-range products, or finalising just the last few details of a new product.
AirBorn Electronics’ Murray says the latter are far more common in Australia, and that group takes a somewhat more pragmatic approach to design.
“Most electronic products do not need to surf the leading edge of the technology,” says Murray. “[For example,] while 0201 components are available, a design may best be made [with] 0603s to keep the board producible and somewhat repairable.”
And often, an Australian PCB designer may only get involved with a project at a late stage. Many of Murray’s clients come to him after having already prototyped their project using a reference design, or produced a few PCB’s, or made a concept unit using commercial-off-the-shelf (COTS) electronics.
“We get quite a few requests to re-engineer existing boards – often without [access to] the original design work,” Murray explains. “Usually the client is trying to produce repair/replacement circuit boards at a reasonable price.”
Or, Murray says, the original design may have had some fatal flaw which needs repairing, such as underrated components, or poor surge resistance. There are also requests to make the PCB water resistant.
“Sometimes the board needs to be an exact mechanical fit – and sometimes the board has to be very nearly identical in all respects,” Murray said. “This requires special software so that we can overlay the new PCB onto a dimensionally accurate photo or scan of the old PCB as the job proceeds.”
Verification and documentation
In years past, clients would receive a board from the designers, then test and check it to ensure it operates as needed. Today, when few can afford the luxury of multiple design “respins”, engineers are in constant contact with the client every step of the way to ensure that the design is proceeding quickly according to the specification.
Engineers, from both the client and the design firms, need to keep logs of the compromises that crop up during the design phase. The PCB design needs to be net checked and design rule checked, with the results verified by both sides.
Precise and up-to-date documentation is necessary to record the design process. While it can be automated by software to a degree, the designer needs to have the discipline to make such documentation part of the workflow.
“If you ‘document later’ it just takes too long,” notes Murray. “You need to document the wiring pinouts as you are doing the job, take photos of the prototypes as you are shipping the boards, and as you are making mechanical measurements of a module or enclosure, it pays to make yourself a template or library part right then and there.”
Documentation can be delivered in various ways, but Murray’s approach involves putting the paperwork online in a password-protected area as the project progresses. The client can then log in during discussions and look at the current state of the PCB layout.
“It really helps [for clients] to see the board – connectors get moved, labelling gets changed, and most importantly big mistakes get avoided,” said Murray.
In some cases, software-supported 3D rendering of PCB designs can also help with the client communication process. Many designers still view such features as ‘bells and whistles’ while others see value because it provides non-engineering stakeholders with a more tangible visualisation of the product.
Many of the changes on the cutting edge of PCB design have little effect on Australian engineers due to the nature of local work. Nonetheless, technology continues to progress and this lack of experience could become a problem.
According to Blackmagic Design’s Roger Hughes, it can be difficult for people to stay current with industry developments if they are not designing on the leading-edge level on a day-to-day basis.
Altium’s Dr Marty Hauff agrees, but says the issue of global competitiveness is symptomatic of an industry-wide problem encompassing more than just PCB designers: Offshoring.
“Asia is advancing at a phenomenal rate and some of Australia’s manufacturing capabilities have moved offshore,” Dr Hauff explains. “This could threaten the critical mass of PCB designers and manufacturing that must be maintained locally to keep the industry viable.”
AirBorn Electronics’ Steve Murray says thus far, Australia has managed to retain PCB design work, since local clients value direct communication with the design engineers. However, the real threat is the offshoring of all manufacturing, which puts the squeeze on the clients who give PCB designers work in the first place.
“I point out to customers that they are trying to pay me less than they would pay a plumber,” Murray says. “But … they are trying to compete against factories (in China) that are much larger, have better access to specialist services (e.g. toolmaking), pay much reduced wages, and where staff not only reliably turn up Monday to Friday – but usually Saturday as well.”
While PCB designers can’t be expected to single-handedly save the Australian electronics industry, there is no doubt they play a valuable part in the high-value-adding applications in which Australia is attempting to specialise in order to retain a niche.
If this policy is to yield success, Australian engineering firms will have to look seriously at investing in more EDA and designer training so that they can break into the high end of the international market and play at the leading edge.