G'day
        I just wanted to elaborate on the Question posted by Phil Dutton
yesterday. I read an article "Design for Testability Guidelines in an
In-Circuit Environment" off the Electronic Engineering Times website.
www.eetasia.com
        The article was written for the may 2000 issue by Joe Kirschling
of Agilent Technologies. In this article Joe suggests that by the use of
Automatic X-ray Inspection the In-Circuit Test can be substantially
simplified. Due too solder defects allready being identified (By X-ray)
nodal access and fixture probe numbers can be reduced, limiting fixture
contact problems and re-test occurrences.
        I am considering requesting X-ray Inspection of our products as part
of the testing procedure to gain the benefits described above. This affects
us now at board level design. In the same article it suggests Oval pads
should be used for BGA Lands to increase the efficency of the X-ray
Inspection
Procedure. The reasons are stated in the article. Unfotrunately the article
shows a diagram of the original round BGA pad in elongated (oval) form but
does not give any calculations for the elongation. As you could imagine with
a BGA I would be looking for the minnimum possible channge to the extension
of the pads to recieve maximum efficency from the X-ray Inspection.
        If anyone could help it would be much apprecited.


BRENDAN ALTUS C.I.D.
ELECTRONICS/CAD TECHNICIAN
IPC CERTIFIED INTERCONNECT DESIGNER

TENIX DEFENCE SYSTEMS PTY LTD
SYSTEMS DEVISION - ADELAIDE
SECOND AVENUE, TECHNOLOGY PARK,
MAWSON LAKES.  SOUTH AUSTRALIA  5095

PHONE        (08) 8300 4567
FAX          (08) 8349 7420
EMAIL      [log in to unmask]
INTERNET   http//www.tenix.com





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