Issue link: https://iconnect007.uberflip.com/i/1190860
48 DESIGN007 MAGAZINE I DECEMBER 2019 Matties: We commonly hear that designers need to know the manufacturing process, and then a smaller group will say that they don't need to be the manufacturing experts. What sort of feedback should a designer look for from a fabricator? Miller: Describing the requirements in a clear manner is important. A lot of times, designers will say, "I need 100 ohms on these layers and 90 ohms on these layers. I need to use blind or buried vias. I need to carry this amount of pow- er. I need a material that can deliver 40-giga- bit data rates," and so on. The fabricators will come back with their recommendations. This is critical because we start with something that falls within the capabilities of the fabricator. As the design progresses, we may need to re- fine the stackup to address unforeseen chal- lenges in the layout that require changes. For instance, we may need to shuffle the stackup due to the results of the signal or power in- tegrity analysis. When we do those kinds of things, we need to go back to the fabricators and make sure that we aren't doing something that's going to cause a DFM problem. Our con- nection and communication with the fabrica- tor are vital. Matties: Regarding post-production, is there any feedback that you look for after the fact from even the OEM or end-user? Miller: There's always feedback. Even though we go through a DFM process during the de- sign process, we'll specifically ask our custom- ers to go back to their PCB fabricator and PCBA assembler for their feedback. We recognize that each shop has their unique capabilities, so we try to get that feedback and incorporate it before we ship the design. When there is a requirement to do a re-spin on a board design, we like to collect the feedback from the fabri- cator or assembler regarding yield issues and see if we can make any changes for yield im- provements on future spins. Matties: When you're working that close up front, it's almost more of a predictive engineer- ing approach than a DFM approach. Miller: To some degree, it's predictive engineer- ing. You're trying to do what you can to make yourself successful up front, which is also a part of our book. Matties: It's had some great reviews, and thank you for putting that out there for the industry. Scott, we certainly appreciate your time today. Miller: Thank you, Barry. I appreciate it. Scott Miller is the author of The Printed Circuit Designer's Guide to… Executing Complex PCBs. Visit I-007eBooks.com to download this book and other free, educational titles. DESIGN007 pact construction with flat ribbon cable, this brushless DC motor is ideal for applications with limited space, such as robot grippers, medical pumps or prosthetics. An adapter board is available for test purposes as an accessory. The DF20 complements Nano- tec's product family of external ro- tor motors, which includes motors with diameters of 32 and 45 mm. (Source: Nanotec) With the DF20, Nanotec now offers a flat external rotor motor with a diameter of just 20 mm. It is available with two different windings for 12 and 24 V and is equipped with digital Hall sensors for simple control. The DF20 features a rated power of 5 W and a rated speed of 5,200 rpm. The open design without rotor housing ensures optimal heat dissipation—even at high speeds. Thanks to its com- Nanotec Develops Flat External Rotor Motor With High Speed