Application notes are the key to shedding light on new topics or new products and software tools in an easily digestible form. As both a consumer and an author of more application notes than I care to remember, Andy Shaughnessy posed an interesting question on whether designers should rigorously follow application notes or verify the content.
Types of Application Notes
I tend to categorize app notes into the following areas:
- How to set up equipment or software
- How to apply a product or software tool to get the best results
- Background notes, which involve explanations of the engineering or science behind a particular task or problem
As always, the approach I recommend depends on the nature of the note. Notes based on how to use a piece of equipment or software do require following to the letter, and personal “interpretation” can lead to disappointment when a system doesn’t set up or function as expected. Customers sometimes call to say a setup hasn’t worked as expected, so applications engineers will remote in to follow what is happening only to see the end-user miss several key steps “because they always miss those out.” For notes aimed at how best to ensure a design meets a specific need, it is always worth looking at several sources as there are often multiple correct ways to solve certain challenges.
Delivery of Content
Historically, application notes were just that: a series of written notes to help explain to a designer or fabricator how to approach a new and perhaps unfamiliar situation. And written notes are still great for this; they’re easily printed out and annotated by the reader at leisure. But increasingly, PowerPoint presentations and video clips can be used to bring application notes to life.
Each has its place, and some content suits one delivery method more than another. Some schools of thought note that different people prefer audio or video or written content for their personal learning style, so having content in several media is often preferable. However, for the content manager, this can be a nightmare to keep updated. Another alternative for designers who may prefer to mix video content with written learning is to embed appropriate video within web pages.
It is worth remembering that some readers may have a block on access to services like YouTube in a work situation, so offering the video stream from an mp4 file on the writer’s website gives an alternate source for content in these situations.
Some notes based on engineering principles stand the test of time, so it is good for the writer to make them application-agnostic—the background information depicted is timeless, with improving technology sometimes more depth needs to be added—but if the original note is well-written, then the new findings or enhanced detail can be added in a supplementary note. For example, when readers want a background to add insertion loss knowledge to impedance control knowledge, in my opinion, the best approach is to link the existing note to a new note which expands on the next level of knowledge required. Both of these types of note stand in their own right, but read together, they broaden the background knowledge and give the reader new to the subject of PCB transmission lines enough information to be able to ask further questions to expand their knowledge of the subject.
Product-related application notes can age as the product is enhanced over the years. Smart product development can minimize the UI changes, so the supporting literature does not age so fast. Often, customers prefer to retain a familiar UI with controls maintained in their positions to maximize the use of muscle memory when engineers use the tools. This is especially the case for infrequently used products. I am sure you are all familiar with web conferencing tools that keep “improving” and moving all the controls around the desktop leading to frustration for occasional users.
Verified Application Notes?
Application notes should always be treated as “best endeavors;” they are not the same as peer-reviewed published papers. Even with peer review, it can be difficult in complex areas to get two engineers to agree on the same solution to an engineering problem.
However, with technical information, it is also worth speaking with the product specialist and applications engineer at your supplier, as they are often in the best place to guide if a technical note has been superseded; perhaps they can also offer some useful secrets from insiders, which are off the record. But a designer should use their own training mixed with common sense, research, and theory combined with the information in the application note to gather information in a timely way to make the best possible design choices.
If, while reading this column, you have had an idea for a useful signal integrity or stackup related application note, please get in contact.
This column originally appeared in the June 2020 issue of Design007 Magazine.