What is PCB Data Management?
Above the simple and obvious answer that data management is the management of data, a better definition is: PCB data management is the acquisition, storage, verification, usage, distribution and maintenance of the data used in the design, fabrication, and assembly of a printed circuit board.
Let’s break this definition down a bit. Before we can talk about the management of the data itself, we should look at what, how, and where we intend to acquire this information. After you’ve been in the PCB industry for any period, you begin to see that much of PCB design is a “cookie cutting” process. The starting point for most PCB designs uses either the same or very similar information and the sources are often universal. Like an acorn that grows to be a mighty oak tree when planted in fertile soil. The initial starting information is also vital to the success of the overall project. I would add that if the starting information for a PCB project is not accurate, then most likely your design will not be accurate either. It is most important to assure that your focus at this point is on the quality of the information rather than the quantity.
Component datasheets are the most essential documents that must be acquired and verified before you intend to use them. These are the go-to documents for everything moving forward, and because of that, they are a critical item; ergo, they must be correct. I have seen too many instances wherein a design was done entirely on the assumption that a datasheet was correct, only to create problems later because it was not verified. The results were disastrous. “Trust, but verify” should be the mantra of every PCB designer.
So, how do we determine the accuracy of a datasheet? A great technique is to use multiple sources to verify the information. Do not rely strictly on a single part vendor source and its datasheet. Look at various sources and vendors for components and pull all the datasheets from each of them. The datasheets can then be compared to verify that they match.
Pro tip: Personally, I would take verification to the next step; I’d monitor the datasheets from those specific vendors and determine if there are any problems with other product datasheets they provide, as they may also have issues.
The next point is storage. After attaining the data, it is vital to have it stored and protected. This is accomplished by the architecture of your component library. It’s virtually guaranteed that your library will be structured entirely differently than the next guy’s. However, no matter what your component library looks like, a few significant things should be in place.
First, one should quickly be able to find specific components. This is often a direct result of utilizing a naming structure or convention that optimizes searchability. One of the more challenging tasks is finding something in a library which has a mish-mash of naming schemes. An excellent resource for this problem is the latest release of IPC-7251 (Through-hole Components) & IPC-7351 (SMT Components). These standards cover the very systematic structure of how the footprints should be named.
Secondly, you want to have a component library that has an easily expandable architecture. This way, as the company grows and the product lines grow, the library grows with it.
You can accomplish both of these objectives by organizing your component list by category and family. For example, each category can contain a variety of families. In doing this, each component will have its specific assigned location.
Verification is a multifaceted term with a variety of subjective meanings. In this context, however, ‘verification’ refers to Data Management and how specific data is verified.
The first rule of verification is that the person who conducted the work should not also be the person to verify it. The person who conducted the work is often blind to their own mistakes, and the result is they will usually miss them again in the verification step. It is always best practice to use a second person who can look at the data with a fresh set of eyes.
The verification process is an audit process. While components or data are under review, they should be quarantined so that they’re not used in released designs. Let me clarify that point; before the PCB design is released for Fabrication, conduct the Audit process on all new components. This way you preserve the PCB design integrity as well as your sanity.
During the PCB design process, you use specific information at particular points of the design. For example, during the schematic part of the design, you are specifically looking at the circuit flow and connectivity. What is most important is the component schematic symbols. For example, the Electronics Engineer would be looking at the parametric information regarding a specific part - making sure that it meets the sought after design requirements for the product.
On the Printed Circuit Board side, you would move over to the PCB Footprint and 3D model information data. The data is used to verify routing and mechanical requirements. This is also the point when a mechanical engineer would join the party and start his or her work.
The distribution of data to particular people is crucial. One way to look at this is to see that data usage is internal to the organization and distribution is external. When working with the distribution of any data, always keep in mind that security is vital. The two big “packages” that come from the data and the design process are the fabrication and assembly information. The standard rule is that these two are sent in opposite directions and should never meet. Because with both packages, an unscrupulous person could use them to reproduce your design.
The final area when looking at the definition is maintenance. Since most of the data used in the PCB design is Dynamic (vs. Static), the data does change. That means there must be a plan in place to determine what changes have occurred and how they affect the update process in the database. This way, your data stays relevant to the company’s needs as well as the ever-changing industry of electronics.