Welcome to 2022. I hope you had a good holiday season, and from my family to yours I wish you all the best for the new year ahead.
I have recently had some great conversations with several readers, and the same question keeps coming up: What does it take to have an excellent component library? I’ve decided to kick off the new year by taking a deep dive into your PCB component libraries and looking in detail at the five pillars of your library. So, along with taking the tree and the decorations down and making your New Year’s resolutions, let's resolve to take an honest look at our component libraries and get them in order.
Importance of Component Libraries
I’m pretty sure we all understand the importance of our component libraries, yet nothing significantly impacts your company's success either as a profit resource or a significant financial loss. That’s because every product first begins in your library.
A sound library just doesn't happen; it takes a lot of know-how, work, and maintenance. Like everything else, our libraries are affected by Newton’s second law of thermodynamics: “There is a natural tendency of any isolated system to degenerate into a more disordered state.” That could not be truer than when working with so much information.
Static vs. Dynamic Libraries
In the early days of PCB layout, the libraries were very static with minimal information. We often copied the component, changed the value, and dropped it elsewhere in the schematic. That was the nature of the beast; as they say, the libraries were compartmentalized, separated schematic symbols and footprint with very little parameter information. Then as the industry demanded more information and electronic systems became more complex, the libraries had to transform to meet the need. The result was the integrated library concept. Within each component were various pieces of information and required models for that individual part. A significant improvement was the addition of part choices, which made the library dynamic and constantly changing. When a component is used in a schematic, we can pull any information needed, including manufacturers and suppliers. I would go so far as to say that our libraries have become a living, breathing resource for us.
This series of columns will look at the five pillars that must be a part of your library. Although every library is different, there will still be these five pillars. Using pillars is a common, useful analogy because it provides a unique mental illustration. The definition of a pillar is a tall vertical structure of stone, wood, or metal used to support a building, an ornament, or a monument.
First, pillars are placed to support a specific building section. To pull one out requires the remaining ones to hold the total weight above. So, the first lesson is each of these pillars is necessary for your library to succeed. You cannot choose which of them you intend to follow; to pull just one out results in the others toppling over.
Second, a pillar provide support for what is above it. What is that? First, the components. The quality of your PCB designs is only as good as the quality of your components in the library. So, these pillars will hold up and support your components and, ultimately, your PCB designs.
Five Pillar Overview
I included a relatively simple acronym to remember the five pillars. It is called the SMART rule.
First Pillar: Singularity
The first pillar that stands before us is “singularity.” The singularity of what? A singularity of data and process. Another way to phrase it is “a single source of truth.”
No matter the size of your design team, if they are working from different data as their starting point, it doesn't take a psychic to determine the results of that one. There is absolutely no way to control the results. It is like multiple people starting at different locations, going in different directions, each having another map, and expecting them to end up at the same place.
The PCB library should be the sole source of all truth. Have you ever noticed this? When someone is dishonest, we say, "That person told a lie," which is plural. However, when someone is honest, we say that a person told the truth. Why is that? Well, there are endless things that can be incorrect about something, but only a single and correct solution: many lies but only one truth.
I have seen time and again the problems directly caused by what I call "rogue libraries." They are libraries of components that are not managed, verified, or controlled. Consider the massive amounts of work necessary to prepare a PCB design. The engineering, layout, fabrication process, followed by assembly and the notorious, unwanted phone calls letting you know that the assembly house was hitting "snags." These problems could be anything ranging from parts not going onto the PCB because of wrong footprints to component tombstoning or falling off entirely when you start to investigate the issue, only to find that someone used their own personal "rogue library.” It usually results in a fatal error for the PCB design and scrapping the entire fabrication. At this point, you begin that long walk to the management office to explain the situation. That is never a good feeling. That library resulted in a lost profit for the company.
Several years back, I joined a company which was considered successful. However, the PCB design area had no structure or organization. As a result, there was a tremendous fallout of boards in both fabrication and assembly. The problem was evident when I remember going over to one of the designers, where he opened a desk drawer filled with bare PCB boards. They were piled up at least a foot high. He let me know that those designs did not make it through assembly due to some problem. When I looked back and put together the numbers (meaning the cost), the estimation of these failures for the PCB design area was around $750,000. It was like I got kicked in the gut by a mule. That was $750,000 that would not come back. It was wasted and gone.
When I investigated further, I determined there were 1,123 PCB libraries of all kinds, and with endless component information, symbols, and footprints. Moreover, probably none of them was correct. Each designer had a personal library. No wonder there were significant problems. The rule of cause and effect was alive and well.
The solution for that company was the first pillar—a single source of truth for everyone to work from. Once I deleted all 1,123 libraries (a story for another day), we immediately began to see improvements in our fabrication/assembly yield numbers.
If you are using multiple libraries right now, decide to take steps to migrate and unify all of them into your single source of truth. However, you will not be sorry to have that first pillar in place.
John Watson, CID, is a customer success manager at Altium.
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