Circuit Board Boundary Scan Tests

Boundary scan test

One of the more problematical issues surrounding board building has grown to be the use of higher and higher pin count BGA's.

The problem is that in soldering these to a board there is no obvious way to check to see if a pin (ball) has actually collapsed and made a good connection between the device and the board. Even with a perfect process there may still be issues because of the quality of the device selected. To compound the issue if more than one JTAG enabled device is used on the board and they are connected to each other but through a virtual net then there may be no physical test access to find out if the ball has reflowed correctly.

Boundary scan has been developed over the last 20 years or so to enable a test per pin to be achieved even if no access is available.

Prima has experience in the use of boundary scan and uses it as a technique to supplement the other tools designed to establish the connectivity on a pin by pin basis of BGA's on boards.

In addition to boundary scan test the supplementary armoury of tools available to Prima are X-Ray, Flying Probe, Ersascope each of which can play a part in establishing the connectivity of the pin before power is applied to the board.