Ironwood Electronics SS-BGA User Manual - Manual (Page 4)

SSI.doc, Rev. A, IP
Rev. B/C/D, RP
Rev. E, VP
3
Tel: (800) 404-0204 • (952) 229-8200
Fax: (952) 229-8201
11351 Rupp Dr. Suite 400, Burnsville, MN 55337
www.ironwoodelectronics.com
are not symmetrical to the mounting holes). The third page shows the compatible BGA specification. The
fourth page details backing/insulation plate dimensions. Check the BGA pattern and the following four
parameters.
1. IC co-planarity value should be less than or equal to that shown in the table.
2. Maximum total height of IC should be less than or equal to that shown in the table.
3. Maximum solder ball diameter of IC should be less than or equal to that shown in the table.
4. Maximum and minimum solder ball height should fall within the range shown in the table.
If any of the above parameters do not match, please call Ironwood Tech Support @1-800-404-0204 to
help select a socket (which may currently be in development).
PCB Requirements
Please refer to page 2 of the socket drawing for all PCB recommendations.
For IC body sizes of 30mm or below, the socket requires 4 mounting holes.
For IC body sizes of 31mm or above, the socket requires 8 mounting holes.
Two alignment holes are used in all sockets. The center for the first is 2.54mm below the upper right
mounting hole center and the second has a center dimension 5.08mm above the lower left mounting hole
center.
The BGA pattern is not symmetrical to the mounting holes. The BGA pattern is same as the one used for
the elastomer socket. It is shifted due to the fact that the wire filaments in the elastomer are at an angle
(the shift is half the elastomer thickness in the positive x-direction). The same footprint used by elastomer
socket is recommended for spring pin socket for interchangeability. Again, please refer to page 2 of the
drawing for recommended footprint.
Thickness
1.5mm minimum. This will change per customer application, environment and usage.
Finish
SnPb plating or Immersion Au or Immersion Ag. Other plating may be used but testing may be required.
Solder mask clearance over pad surface is acceptable.
Cleanliness
Isopropyl Alcohol or equivalent should be used to clean the board surface prior to attaching socket.
IC and PCB Reflow Requirement
If the same IC is used for number of cycles, crown tip on spring pin damages the Sn63Pb37 solder balls on
IC and conical tip damages HASL(hot air solder level) pads on PCB. From our test results, we recommend
reflowing IC solder balls every 10 cycles and HASL PCB every 30 cycles. Gold plated PCBs will not
need any reflows.