The Evolution of Test

To a certain extent, early advancements in T&M equipment by pioneering companies like Hewlett-Packard, Teradyne and others transformed the electronics industry. During the 1960s, demand for electronics grew rapidly, reaching a point where bottlenecks in the manufacturing process were impeding the growth of the industry. That is, manufacturing volume was hard pressed to keep pace with demand. One of the bottlenecks in the process was test.
 
In those early days, test was slow and laborious. An army of technicians using the same tools that designers had employed during development would manually test subassemblies and systems in the midst of the manufacturing flow. Soon, it was obvious that test automation would be essential to higher manufacturing volumes. The result was the creation of a new equipment category, automated test equipment (ATE).

Like the electronic systems of the day, early ATE systems were big and boxy. They were large hardware-intense

As the diversity of electronic products and manufacturing volumes increased in the 1980s, the limitations of hardware test equipment became more apparent. Hardware test systems were and still are hard-wired to a few specific functions and to a narrow range of measurements. A new product based on advanced technology often required that the manufacturer procure another hardware test system compatible with new technology. Regularly replacing hardware test systems inflated the cost of test while manufacturers were trying to drive down the cost of their products to stimulate greater demand in the marketplace. The concept of virtual instruments was a response to this situation.

During the mid-to-late 1990s, basic technology advancements like new chip packaging technologies, circuit board design techniques and higher-speed, more electrically sensitive input/output (I/O) buses connecting chips on circuit boards caused problems for legacy ATE systems and hardware-limited test methods in general. Specifically, access for physically probing chips and boards was disappearing. Pins on chips, which previously could be probed for test purposes, were suddenly hidden beneath the silicon in chip-scale packages like ball grid arrays (BGA). Another example of vanishing access for probe-based systems like ICT testers was the rapid disappearance of test pads on circuit boards. To add functionality to electronic systems, boards were densely populated with chips, leaving little or no room for test pads at all. Moreover, high-speed I/O buses were becoming so sensitive to the capacitive coupling effects and reflections induced by test pads that many new board designs banished pads completely.
 
Fortunately, while the progress of technology was dictating another step in the evolution of T&M, certain test technologies and methods were emerging that would enable the application of   instrumentation embedded in semiconductors in non-intrusive T&M technologies. Chief among these technologies was boundary scan (IEEE 1149.1) or what is often referred to as JTAG after the Joint Test Action Committee which initiated development of the standard. A software-driven technology, boundary scan provides non-intrusive probe-less access to embedded instruments in

Of course, electronic technology will continue to advance and T&M will evolve right along with it. Chips will get smaller and new packages, like stacking multiple die in the same carrier, will only limit further the effectiveness of test equipment that relies on any sort of a physical probe. High-speed buses and chip interconnects will only get faster, making them more sensitive to probing and narrowing the means of validating their signal integrity. And circuit board design and fabrication techniques will continue their current course toward greater complexity, many-layered boards and other techniques that simply defy physical probes.

The ScanWorks platform for embedded instruments is at the vortex of the swirling forces at work in the T&M industry. At a time when the effectiveness of traditional legacy T&M equipment is rapidly diminishing, the ScanWorks platform capitalizes on the non-intrusive test standards and technologies developed over the last 15 to 20 years and incorporates emerging new techniques like IJTAG and others to give system and subassembly designers, manufacturing test engineers and others a clear path to the future of advanced, software-driven test technologies.