Printed Circuit Design & Fab Online Magazine - Current Issue

Designer’s Notebook

The quarantine may have created the biggest shift in how PCB design works.

As a career PCB designer, I’ve seen a lot of waves break over the electronics industry, but not since the very foundation of electronic computer aided design (ECAD) have I seen such a significant paradigm shift in our work practices. From the mid-20th century onward, computers have become involved with our design efforts. Aerospace and automotive industries led the way along with universities; about the only places where computers were available in those days.

Read more: Home Design

Aligning signals to attain perfect synchronicity.

Clocks are essential gatekeepers of the digital domain. Setting the pace for all that follows the clock can be a single trace or a partnership of two traces that carry complementary signals. Either way, the function of a clock is to switch from high (a logical 1) to low (0) up and down continuously; on, off, on, off, all day long. Signals controlled by the clock switch only when activated by the code, meaning that other signals do not change their state with every cycle of the clock.

Read more: It’s About Time: Clocking a PCB Design

Communicating the design intent, clearly and concisely.

The CAD system can do a lot for you; then you’re on your own. Eyeballing the layers two or three at a time will help you find the hidden traps. A camera-ready board is just the beginning. Documenting the PCB requirements with dimensions and other details, including hole chart(s), stack up diagram(s), a list of intentional shorts, etc., puts the necessary guardrails around the fabrication and assembly.

Fabrication notes will change with the technology used for the PCB. The general thrust of this list of example notes is for a multilayer board targeted for consumer electronics with components on both sides and controlled impedance on inner- and outer layers.

Read more: Creating a Documentation Package

Grounding and routing tips for sensitive parts.

Years ago, I set out to become a world-famous PCB designer. The journey, however, took much longer than that. Starting near the beginning, the second lesson I learned about electronics came on the first day on the job in electronics. I bet you’re wondering what I did in electronics on my first day.

My contribution was to put completed printed circuit board assemblies into pink bubble wrap bags. The bags were sealed with resealable ESD warning stickers and placed in individual boxes. Labels on the boxes had blanks for the information, which was copied from the board to the label. Completed sets of eight boxed boards were again boxed in a larger box, which was labeled with the content part numbers, revisions and so on.

As an aside, the next stop for the boxes was the shipping department and, finally, phone company offices around the country. Called offices, they were more of a precursor to today’s data centers. The build-out was a result of the US government forcing the phone company to break itself into regional businesses.

Read more: Electrostatic Discharge: As Old as the Hills and Still Something to Consider