Selecting a bga socket, Socket mechanics – Ironwood Electronics SG-BGA User Manual User Manual
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Tel: (800) 404-0204
www.ironwoodelectronics.com
Selecting a BGA socket
The IC package drawing is required to select the correct GHz socket. Go
Select the “Products” link, then under the “Browse” menu, select the “GHz BGA & MLF socket” link. For
1.27mm, 1mm, 0.8mm and 0.75mm pitch BGA devices, select the “SG-BGA-6xxx” link. For 0.65mm, and
0.5mm pitch BGA device, select the “SG-BGA-7xxx” link. In the table, select the part number that corresponds
to your IC size (length mm x width mm), array size (rows x columns) and pitch (mm). Note: More than one
part number may match your criteria. A frame on the top of the page will show the socket price and links to
PDF and JPEG files.
The JPEG file is a picture of socket. The PDF file will have three pages. The first page shows the socket cross
sectional views and the material details. The second page shows the recommended PCB layout (Note: BGA
pads are not symmetrical to the mounting holes). The third page shows the compatible BGA specification.
Check the following four parameters.
1. IC co-planarity – the value should match or be less.
2. Maximum total height of IC should match or be less.
3. Maximum solder ball diameter of IC should match or be less.
4. Maximum and minimum solder ball height should fall within the range.
If any of the above parameters do not match, go back to the table and select a different part number that
matched the initial criteria and repeat the four parameter checks. If a part number cannot be found to match IC
parameters, please call Ironwood Tech Support @1-800-404-0204.
Socket Mechanics
GHz BGA sockets provide 6.5 to 10 GHz bandwidth in a small, cost
effective ZIF socket for prototype and test applications. The GHz
BGA socket is a simple mechanical socket based on elastomer
connector technology. The GHz socket is a solder-less socket that
can be mounted onto a PCB using screws and nuts. PCBs will require
mounting and alignment holes
at proper locations (see page 2
of
the
drawings
for
recommended
PCB
layout
information). The typical
GHz socket is 5mm larger
than the maximum IC size. If
there are pre-existing holes in
the PCB, a GHz socket can be custom designed to accommodate those
holes (please call Ironwood Tech Support @1-800-404-0204).
Figure 1 shows a typical GHz BGA socket. The Z-axis conductive
elastomer used in the socket, as a contactor between the IC package and
the circuit board, is a low resistance (<0.01
) connector. Figure 2 shows an SEM picture of the elastomer. The
elastomer consists of a fine pitch matrix (0.1mm x 0.1mm) of gold plated wires (40 micron diameter), which are
embedded at a 63-degree angle in a soft insulating sheet of silicone rubber. Another elastomer used for high-
Figure 1: GHz BGA Socket
Figure 2: SEM
Picture of Elastomer