[BGA]This section allows the user to define parameters of the BGA package; the AIF reader will be able to draw the ball pads and package outline.
Many times a die designer will know the signal name and even the ball assignment for his die pads but does not have the "coordinates" of the ball pads. However often he needs to explore different package options - package size, pitch, ball diameter ...
the [BGA] section in the AIF file allows him to quickly define a package from well known parameters; AIFVU will then draw the package footprint along with the die. This allows the die designer both to see the die together with the package and also to see a ratsnest from die pad to ball pad (assuming nets have been defined.)
[BGA] NAME=BGA name (ref designator) WIDTH=23000 package outline width in same units as AIF file HEIGHT=23000 package outline height (y) PITCH=1270 center-center spacing between ball pads CHAMFER=UR 250 chamfer on the outline. You can specify all 4 corners POPULATION= 17 17 number of balls along x and y DEPOPULATION= 9 9 remove this many balls in the interior REPOPULATION= 0 0 add back in this many balls (typically ground) BALL=CIRCLE 750 ball pad shape and size A1=UL location of A1 (looking from above the package)
If population is even; depopulation and repopulation should be even. If population is odd, depopulation and repopulation should be odd.
rectangular packages are supported - but pitch must be equal in both directions.
the package outline can have up to four chamfers - UR 1000 LL 500 UL 250 LR 600
New BGA Polygonal Outline[added 04/26/04]
In order to support more complicated packages (in this case a module containing two chips with an irregular outline) we have added a new parameter to the BGA section called:
with the following syntax:
OUTLINE=POLYGON <num_pgons> <width> <num_pts> x0 y0 x1 y1 ... xn yn
[BGA] OUTLINE=POLYGON 1 0.1 7 -9 -5 11 -5 11 5 7 8 -5 8 -5 6 -9 6
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