Issue link: https://iconnect007.uberflip.com/i/929192
JANUARY 2018 I DESIGN007 MAGAZINE 27 our game and getting better at the core skills of PCB design for manufacturing, test and assem- bly. And despite the increasing difficulty with cluttered channel space in the wireless spec- trum, we're pretty good at designing for elec- tromagnetic compatibility and signal integrity as well. Yet, board designers still must fight to reduce design time and re-spins due to other pesky problems. The real bottlenecks in the process of getting an electronic product to market are exacerbated by the nature of IoT devices: mechanical form and fit, extended production runs and parts availability, as well as increasing complexity and density. On the product form and fit side, there's the obvious issue that the PCB assembly must fit within the designed structure of the overall product. And for a long time, EDA vendors have been aware of the need for proper col- laboration between the PCB designer and the MCAD flow. Most designers even to this day are relying on transfer of mechanical CAD data between the ECAD and MCAD tools for syn- chronizing the physical aspects from mechani- cal CAD to PCB design and back. While these formats such as IDF/IDX and STEP have gone a long way to improving the fortunes of prod- uct designers, they are still intermediary for- mats and suffer loss of fidelity. With regards to production run extension and parts availability, there can be serious show- stoppers. Most IoT devices that are accepted by their markets will experience demand surges. This is a delight to manufacturers and designers, yet poses significant supply chain problems that often lead to design re-spins. Most seasoned design- ers have experienced this, having had to modify a product simply because one obscure component is not available in time for the sec- ond production batch. No serious business can tolerate the opportu- nity cost of waiting for that part to become available again. Then there's the age-old issue of "smaller, faster, better" market- ing requirements putting pressure on designers to squeeze more into less space, without neglecting signal integrity and compli- ance with FCC, CE, C-Tick, UL, and other EMC and safety regulations. What can we do to increase design through- put, allow busier people to design more boards and get them right first time more often to meet the looming demands? The short answer is to provide and improve user-guided automation. Multi-Board Design & Collaboration Given that at least half the IoT products have or will have multiple PCBs within the assembly, designers need multi-board design automation in their tools. This automation enables rapid design without unnecessary re-spins by allow- ing the PCB designer in a native PCB environ- ment to combine multiple PCB assemblies into a multi-board assembly. In the multi-board assembly, the PCB substrates can be aligned correctly using planes, edges and axes. Mount- ing holes and critical components such as board-to-board connectors can be moved into alignment with each other and with mechani- cal features of the overall enclosure assembly, as shown in Figure 2. This physical virtual prototyping allows for finding show-stopping problems. For example, Figure 2 also shows the main power connector in the design interfering with the rear shell of the plastic enclosure of this touch-sensor based light dimmer. We can also see board interferences with the front side Figure 2: Multi-board clearance visualization (Source: Altium LLC, 2017).