Why Non-Test Engineers Need to Understand Design for Testability (DFT) and Built-In Self Test (BIST)

We have been teaching highly technical course on Design for Testability (DFT) and on Built-In Self Test (BIST) to test and design engineers for decades. We have been effective in sensitizing design engineers and quality conscious technical managers. In many cases the engineers left our classrooms all excited about how they will improve this aspect of test concern in their companies, only to be greatly disappointed on the reception to DFT ideas by their management – especially non-technical management. As the age-old argument against DFT goes, why spend money now for a possible benefit many years down the line? It appears that the technical details about scan and boundary-scan (JTAG) has not prepared our course graduates to stand up to what sounds like a good financial argument. Explaining the technical details does little to persuade such managers even when they have a technical background. Unfortunately, their opinions, however misguided, holds muster and ultimately DFT engineers may find that it is not possible to expect managers to support testability – at least not to the extent technically possible.

The scenario I described above usually occurs in less-than-high-volume board and system manufacturing operations. It appears to be easier to make an effective case for DFT for high-volume chip manufacturing. It is interesting to hypothesize about why an IC design engineer is compelled by managers to make the circuit testable, whereas board and systems design engineers are told to place DFT on the back burner. What we should do instead, is to educate management on the benefits of DFT, especially if they don’t understand the technical aspects of this activity.

With more “things” out there, more “things” can fail. The internet-of-things - more descriptively the internet-of-everything – causes failures not only in the “thing” itself but in everything our "thing" is networked with. 

Why is this crucial? With more “things” out there, more “things” can fail. The internet-of-things - more descriptively the internet-of-everything – causes failures not only in the “thing” itself but in everything our "thing" is networked with. In fact, one of the greatest problems we face today is not knowing what the root cause of a failure is. Diagnosing the problem is usually the biggest problem. What has that got to do with DFT? Well, that is one of the most important reasons for DFT and many in management do not realize this. So if your product is part of a network and you can tell for sure whether your product is the cause or is absolutely not the cause, you not only save time for your staff, but more importantly you assist your customers even if some other item on the network caused the failure.

Tow explain how DFT can help such issues, we are introducing a short 90 minute Webinar entitled “ Design for Testability (DFT) and Built-In Self Test (BIST): Not only for Test Engineers.” It will be presented on Tuesday, March 12, 2019 worldwide and you can register here. 

The course is going to explain DFT, including DFT techniques that all decision makers – technical and non-technical should know. It will not require technical background, but it will not sidestep those technical issues that are important for managers to know. Because JTAG/boundary scan is an important DFT tool, for example, we will discuss its functions without dwelling on finite state machines and scan details. It will also cover Built-In Self Test topics. There will also be some discussion about test and testability economics, but the focus is on explaining DFT methods. 

Test and DFT engineers are, naturally, welcome and will benefit from knowing the manner in which the topic is discussed so they can have a meaningful follow up dialog with those who attended. Managers of all types who interface with test, will find the topics useful. Marketing people and Quality Assurance, who need to justify product quality will find useful talking points in the webinar. Finally, all design engineers who are not yet using DFT should attend. They may opt for a more technically oriented discussion, but this short webinar will provide them with a good background and perhaps answer why they should care about DFT.

About us: A.T.E. Solutions, Inc. provides test, ATE and testability education in addition to consulting, research and development. For a complete background, visit us at www.BestTest.com.

Please share this blog with others in your organization and I look forward to seeing you in the webinar, on March 12, “Design for Testability (DFT) and Built-In Self Test (BIST): Not only for Test Engineers.” If this date/time is not convenient, we can bring the webinar to your facility as an on-site webinar.