To
simplify building of test fixtures and avoid problems in
the test process, the following recommendation is made
for PCB board design:
Guiding holes:
- Minimum two
non-plated guiding holes per board, placed as far
as possible from each other
- Recommended size of
minimum 3 mm
- Recommended clear
space around the holes should be 6 mm
- Placement should be
such that the board can be turned only one way in
the test fixture
- For panel boards
there should be two guiding holes per board, plus
two guiding holes for the total panel
Test points:
We recommend to use the following (in priority sequence):
- Test pads (test pads
should be tin or gold plated)
- Component legs for
hole mounted components
- Tin filled vias
To avoid double sided test
fixtures, the test points should be placed on the same
side of the board.
Distances and dimensions for board layout:
- Minimum 5 mm from
board edge to components (only for direct vacuum
fixtures)
- Minimum test pad
diameter size should be 1 mm or larger
- Minimum centre
distance between test points for 100 mils probe
should be 2,3 mm
- Minimum centre
distance between test points for 75 mils probe
should be 1,9 mm
- Minimum centre
distance between test points for 50 mils probe
should be 1,27 mm
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