Test Technology Associates Keeps Designs in Line

By Jay Hipps, Hacienda Network Staff Writer

Printed Circuit Board Diagnosticians Play a Key Role in Manufacturing

Manufacturing has come a long way since Henry Ford invented the assembly line. As products have become more complex, so too has it become necessary to find new ways of testing them.

It's easy to see if some things are made properly - a visual inspection can be all that's needed. What happens, though, with a printed circuit board that can contain hundreds of separate chips and other components?

That's where Test Technology Associates comes in. TTA writes software that allows for testing of each individual component on a circuit board as well as the board as a whole. They play a key role in the manufacturing of everything from computers to medical ultrasound systems. They're the largest company in the world to provide this service.

"On printed circuit boards, you have points on the back side which allow you to access each of the components," explains David Shaw, manager of the company's Hacienda facility. "You can test every single component on that board- you can check all the large integrated circuits and all the various components."

It's a fascinating process. A special fixture is created for each circuit board which enables wire probes to touch each contact point on a board. The fixture is placed on a testing machine from GenRad, TTA's former parent company, or Agilent. A sample board is placed into the fixture and then a vacuum is applied, which ensures solid contact between the board and each of the probes.

This is where TTA's expertise comes in. The ability to communicate to each component individually allows them to provide input to and monitor output from each component, based on their knowledge of what the chip is supposed to be doing. Their software, which is custom-developed for each model of board that is tested, identifies any faulty parts on the board.

"The alternative way of testing these is what they call a functional test, where they basically plug in the board and see if it works," adds Shaw. "For an engineer to determine which individual component is faulty, it's going to be very costly. We can determine that typically in 15 or 20 seconds, so it makes a big difference."

Typically, their customers come to TTA after a design has been finalized but before it is put into production. Once TTA's software is complete, it is sent to the facility where the boards are produced and used to test faulty boards to determine which component needs to be replaced. TTA's customers include Dell, Lucent, and a variety of contract manufacturers both in the U.S. and around the world. Headquartered in Lewisville, Texas, they also have offices in Orlando, Florida, and Guadalajara, Mexico.

Photo: David Shaw places a motherboard into a fixture before testing. TTA's software is custom-designed for each printed circuit board they test.

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