Ironwood Electronics SS-BGA User Manual - Manual (Page 3)

SSI.doc, Rev. A, IP
Rev. B/C/D, RP
Rev. E, VP
2
Tel: (800) 404-0204 • (952) 229-8200
Fax: (952) 229-8201
11351 Rupp Dr. Suite 400, Burnsville, MN 55337
www.ironwoodelectronics.com
Socket Mechanics
SS-BGA sockets provide high bandwidth in a small, cost
effective ZIF socket for prototype, test and burn-in applications.
SS-BGA socket is a simple, mechanical socket based on spring
pin technology. SS-BGA socket is a solder-less socket that can
be mounted on to a PCB using supplied hardware. The PCB
should have mounting and
alignment holes at proper
locations (see page 2 of the
drawing for recommended PCB
layout information). The typical
SS-BGA socket footprint is only
5mm larger than the maximum
IC size. It is compatible with
the alternate SG-BGA
(elastomer) socket footprint. If
there are pre-existing holes in
the PCB, an SS-BGA socket can
be custom designed to accommodate those holes (please call Ironwood
Tech Support @1-800-404-0204).
Figure 1 shows a typical spring pin socket. The spring pin functions as the
contactor between the IC package and the circuit board. The spring pin used in the socket is a low-
resistance (<0.02
Ω) connector. Figure 2 shows a picture of the 1mm center – double ended spring pin.
Double ended spring probes are primarily comprised of two plungers, barrel and spring. The spring (gold
plated music wire) is sandwiched between two plungers (gold plated hardened Beryllium Copper) inside
the barrel (gold plated Phosphor Bronze). The spring probe has high current rating (4.0A continuous,
single probe in free air @ ambient). The operating temperature range is -40
° to 150° C.
The solder balls from the IC package come in contact with the crown end of spring pin. The bottom end of
spring pin contacts the circuit board pad, completing an electrical path for the signal. The socket
mechanism can be summarized as a downward force applied on the IC which compresses solder balls on
the spring probe which in turn compresses on the circuit board and thereby making electrical connection.
Selecting a BGA Spring pin socket
Please refer to the IC package drawing to select the corresponding BGA spring pin socket. Visit the
Ironwood website:
www.ironwoodelectronics.com . Select the “Products” link. Next, under the “Browse”
menu, select the “GHz BGA & MLF Socket (SG, SS)” link. In the table, select the part number from the
first column which corresponds to your pin count, IC body size, array size, and pitch. The top webpage
frame will show a link to the drawing, a picture of the socket (JPEG format), and provide low-volume
price information. The drawing is a four page PDF file. The first page shows the socket cross sectional
views and the material details. The second page provides the recommended PCB layout (Note: BGA pads
Figure 1: Spring Pin Socket
Figure 2: Picture of 1mm
center - Spring Pin