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Socket Mechanical Design
3.3.1.5
Socket Seating Plane for Package
The socket seating plane for the package defines the minimum package height from
the main board. See
board. The datum is defined by the top surfaces of seating plane standoffs which cause
a hard stop of package over the socket when the package and socket are loaded. There
are primary socket seating planes and secondary socket seating planes.
• Primary seating planes are located at areas where contacts are depopulated and
around socket cavity and center split locations as illustrated in
Appendix
• Secondary seating planes are interstitial seating planes, which are small islands
within a pitch range and around each core pin except for manufacturing keep-outs.
Refer to
Both primary and secondary seating plane areas and numbers of the seating planes are
maximized to avoid significant creep of the housing material when being loaded.
However, the seating plane standoffs should not touch the LGA lands on the bottom of
the package. Intel recommends that the nominal height of interstitial seating planes be
the same as the nominal height of primary seating planes, but the highest points of
interstitial seating planes will be no higher than the highest points of primary socket
seating planes. The seating plane co-planarity needs to meet the specification after the
socket has been mounted (soldered) to the board. Refer to
3.3.1.6
Strength of Socket Housing Material
The material of the socket housing is required to have a minimum yield strength of
35 MPa at 90 °C to minimize the risk of seating plane deformation.
3.3.1.7
Socket Standoffs
Standoffs will be provided on the solder ball side of the socket base to ensure the
minimum socket height after solder reflow and to prevent socket housing over
deflection after being loaded. It is required that wherever there is a top side primary
socket seating plane for a package, there should be a corresponding standoff on the
bottom side. A gap between the solder-ball seating plane and the standoff prior to
reflow is required to assure sufficient ball collapse during the surface mount process.
3.3.2
Markings
All markings required in this section can withstand a temperature of 260 C for
40 seconds, which is typical of a reflow/rework profile for solder material used on the
socket, as well as any environmental test procedure outlined in
degrading. Socket marks are visible after it is mounted on the main board. Each socket
body half is marked with the following:
• Socket Name: LGA3647-1 (preferred font type is Helvetica Bold [min. 4 pt, or
1.5 mm]).
This mark is stamped or laser-marked as shown in the drawings.
• Manufacturer's Insignia (font size at supplier's discretion).
This mark is molded or laser-marked into side wall of the socket.
Both marks are visible after the socket has been surface-mounted to the main board,
with bolster plate assembly and pick-and-place cap installed.
• Lot Traceability - Each socket body half is marked with a lot identification code to
allow traceability of all components, date of manufacture (year and week), and
Order Number: 334785-002
Section 2
for details on package and IHS height above the main
D.
Appendix D
for more details.
Appendix D
Appendix
®
®
Intel
Xeon
Phi™ Processor x200 Product Family TMSDG
Figure 3-1
and
for details.
A, without
25
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