PCBs starting to get engineering treatment
As electronic circuits have become faster and denser, the PCB has become more than just a convenient carrier for them. Today’s designs need to treat PCBs as passive components equally critical to a circuit’s successful operation as any capacitor, resistor, or inductor. To address this issue by elevating the role of PCB design, a new trade association has arisen.
It’s hard to imagine electronics without PCBs, but they were a late-comer to the party. In the first decades of radio and computers, active devices (tubes) plugged into carriers mounted on a chassis, with those carriers hard-wired together and to the passive components. Often the final chassis was made of metal that could serve as a convenient ground connection, but they could be made of something else. A common prototyping technique, for instance, mounted carriers on a convenient slab of wood frequently found in kitchens of the era and drove in nails to serve as connection points – the origin of the term “breadboard.”
But the lure of using an interconnection scheme that could easily be mass-produced prompted exploration of the circuit-board concept with patents appearing as early as 1903. Manufacturing limitations, however, prevented them from becoming practical for another 40 years. Yet by 1948, the PCB had become important enough to the electronics industry that the US National Bureau of Standards (now NIST) took steps to support the practice. Within a decade an industry group – the Institute for Printed Circuits (now IPC International) – arose to train designers and develop industry standards for the design and fabrication of PCBs.
Source: Printed Circuit Engineering Association (PCEA)
What evolved was a practice of separating the circuit design from the board design. The electronics designer handed their schematic and mechanical specifications to the board designer, who laid out the board following industry standards and best practices for manufacturability and performance. They became coordinated, but mostly independent, tasks.
Increasing clock speeds and industry economics have since strained the practice. Higher clock speeds required ever more engineering skill from board designers, and industry economics have increasingly forced circuit designers to design their own boards. Many EDA tools have appeared to help ease the effort, but the demands are continually increasing. Circuit and PCB designers must understand both disciplines and how they interact.
This growing need for understanding has prompted the establishment of a new industry group devoted to PCB engineering, the Printed Circuit Engineering Association (PCEA). Its stated mission is “to promote printed circuit engineering as a profession by encouraging and facilitating the exchange of information and the integration of new design concepts through communications, seminars, and workshops.” To meet that goal, the PCEA has targeted its activities not just to the PCB design profession, but to all the engineering disciplines that are involved.
Since its creation early this year, the PCEA has already grown substantially. It has established nine local chapters across North America, with at least a half-dozen more in the works. It is free to join and its activities are paid for with voluntary member donations and corporate sponsorship from companies like EMA Design Automation, publications like Printed Circuit Design and Fab, and trade shows like PCB West.
Among the services the organization provides the engineering community are links on its website to free design resources like PCB design tools and specialized calculators and technical aids. The PCEA website also offers free materials like technical papers, books, and presentations, and future plans include online classes.
While it is too soon to tell if the association will be a success, its establishment makes one thing clear: PCB design needs to evolve from a skilled trade to a full engineering discipline to meet increasing technical demands on boards. Further, PCB professionals need to become an integral part of electronics systems design. The days of “over the transom” handoff of schematics with the expectation of receiving a working board back are passing. Circuit boards are becoming a critical component of modern designs and deserve the same careful engineering approach.
This article was originally published on EDN.
Rich Quinnell is a retired engineer and writer, and former Editor-in-Chief at EDN.
New products & solutions, whitepaper downloads, reference designs, videos
Register, join the conference, and visit the booths for a chance to win great prizes.