How PCB Design Has Changed Over the Last 50 Years

In the 1970s, designing a circuit board involved drawing schematics and physical artwork by hand. Today, PCB designers work in sophisticated digital environments that can account for electrical, mechanical, and manufacturing constraints simultaneously. This evolution has closely followed the development of electronics themselves, as products have become smaller, faster, more integrated, and more complex.

At MJS Designs, we have five decades of experience designing PCBs and keeping pace with the technologies and techniques used throughout the industry.

Drawing the Board: The 1970s

In the 1970s, PCB design was largely a manual drafting exercise. Designers commonly worked at drafting tables using pencils, stencils, mylar film, adhesive tape, and other specialized drafting materials. Schematics and board layouts were drawn by hand, with the physical board represented through artwork showing traces, pads, holes, and component locations.

Component footprints and copper traces had to be positioned manually using grids, tape, and carefully measured dimensions. Once complete, photographic processes were used to scale and transfer the artwork into forms suitable for PCB fabrication. Multilayer boards existed, but the number of layers, connections, and components was much more limited than on modern boards.

Much of the design process depended on the designer’s experience and ability to identify potential problems before fabrication. Spacing, routing, component placement, and connectivity had to be checked manually, and revisions could require substantial rework. A board was constrained not only by manufacturing technology, but also by what a person could reasonably draw, measure, and verify without digital assistance.

Putting PCB Design on a Computer: The 1980s

The increasing use of computer-aided design in the 1980s began to fundamentally change how PCBs were created. Instead of representing a design solely through physical artwork, designers could work with digital representations of components, electrical connections, and board geometry.

Early schematic capture and PCB layout systems were comparatively limited by modern standards, and computers did not eliminate manual engineering work. Designers still had to define components, create footprints, position devices, and route connections. However, digital data introduced an important new advantage: designs could be edited, copied, stored, and documented without recreating physical artwork.

Reusable component and footprint libraries also became increasingly important, allowing designers to avoid repeatedly constructing the same basic geometry. As surface-mount technology gained wider adoption, PCB layouts could accommodate smaller components and greater component density, further increasing the value of digital design tools.

Although many aspects of the process still required considerable manual effort, the designer’s workspace was gradually moving from the drafting table to the computer screen.

Designing More Complex Boards: The 1990s

During the 1990s, desktop computing made PCB CAD increasingly accessible, and digital design became the standard approach for a growing portion of the industry. Schematic capture and PCB layout tools became more closely integrated, allowing electrical connectivity to drive physical layout rather than requiring designers to maintain separate representations manually.

Design Rule Checking, or DRC, also became an increasingly important part of the design process. Rather than relying entirely on visual inspection, designers could use software to identify problems such as insufficient clearances, incorrect connections, and other violations of defined design constraints.

At the same time, surface-mount technology continued to expand, with smaller packages and increasingly dense layouts becoming common. Multilayer boards also became more prevalent as designers needed additional routing capacity to accommodate growing numbers of connections.

The transition to digital manufacturing data was yet another significant development. Gerber files and numerical drill data became increasingly important for communicating PCB artwork and fabrication information to manufacturers. As a result, designers could manage substantially more components, connections, and physical constraints than earlier generations while maintaining a consistent digital record of the design.

Designing for Electrical Performance: The 2000s–2010s

As electronics became faster, PCB design increasingly had to account for electrical behavior as well as physical connectivity. Higher clock rates and faster signal edges meant that a PCB trace could no longer always be treated as an ideal wire. Transmission-line effects, controlled impedance, propagation delay, and signal reflections became important considerations.

Design practices such as differential-pair routing, trace-length matching, controlled impedance, and careful management of return paths became increasingly common. Crosstalk and electromagnetic interference also received greater attention, particularly in high-speed and high-density designs.

At the same time, signal-integrity and power-integrity tools became more accessible. Designers could simulate circuits and interconnects, analyze impedance and coupling, and perform post-layout checks to identify potential problems before hardware was built. This represented another major shift: the PCB was increasingly treated as an active part of the electrical system rather than simply a physical platform for connecting components.

More sophisticated multilayer stackups and specialized materials also became common in demanding applications. At the manufacturing level, requirements such as RoHS compliance and lead-free assembly introduced additional considerations for both design and fabrication.

Designers also began incorporating Design for Manufacturing (DFM) and Design for Assembly (DFA) considerations more deliberately into the design process. A board increasingly had to be evaluated not only for whether it would function electrically, but also for whether it could be manufactured and assembled reliably and efficiently.

Highly Integrated and Automated Design: The 2020s

Modern PCB design combines many of the challenges that emerged over previous decades. A single board may contain extremely dense BGA packages, fine-pitch components, high-speed interfaces, complex power-distribution networks, and multiple mechanical constraints. Technologies such as HDI, microvias, rigid-flex construction, and advanced laminate materials allow designers to accommodate requirements that would have been impractical or impossible decades ago.

The design environment has also become increasingly multidisciplinary. ECAD and MCAD systems can exchange three-dimensional design data, allowing engineers to evaluate component clearances, enclosure fit, connector locations, and other mechanical constraints while the electrical design is still evolving.

Automated verification is now present at many stages of the process. DRC can evaluate large numbers of geometric and connectivity rules, while DFM analysis can identify fabrication and assembly concerns. SI and PI simulation can evaluate electrical behavior, and increasingly sophisticated routing and placement tools can automate portions of tasks that once required extensive manual effort.

Automation is also beginning to incorporate machine learning and AI-assisted techniques. These technologies are still developing, but they point toward a design process in which software takes on more repetitive work while engineers focus increasingly on constraints, tradeoffs, and engineering judgment.

The PCB Designer’s Toolbox: Then and Now

The contrast between PCB design in the 1970s and today is striking.

While the tools have changed over time, the PCB designer’s role has not: converting electrical concepts into physical structures that must meet functional, mechanical, and manufacturing requirements.

Conclusion

Over the past 50 years, PCB design has progressed from a largely manual drafting activity to a sophisticated digital engineering discipline. Each generation of tools emerged in response to increasingly demanding electronics, from higher density and smaller components to faster signals and more complex mechanical requirements.

Despite these changes, the fundamental objective remains the same; designers past and present translate electrical designs into physical boards that work reliably and can be manufactured successfully. At MJS Designs, we leverage our decades of experience to provide quality PCB designs that withstand the test of time. Contact us today to learn more about how our experience can benefit your next design.