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Mechanical Requirements
12 LGA 771 Socket Mechanical Design Guide
operating temperature, while mounted on an FR4-type motherboard material. The
creep properties of the material must be such that the mechanical integrity of the
socket is maintained for the use condition outlined in Section 5.
The color of the socket housing will be dark as compared to the solder balls to provide
the contrast needed for surface-mount (SMT) equipment pick and place vision systems.
Components of the socket may be different colors as long as they meet the above
requirement.
3.2.1.2 Package Installation / Removal Access
Access will be provided to facilitate the manual insertion and removal of the package.
To assist in package alignment and proper orientation during package installation into
the socket:
• The package substrate has keying notches along two opposing edges of the
package and offset from the package centerline (refer to the processor datasheet
for further details).
• The socket utilizes one feature designed to mate with the keying notch along the
inside wall of the package seating cavity (refer to Appendix A).
3.2.1.3 Socket Standoffs
Standoffs will be provided on the bottom of the socket base in order to ensure the
minimum socket height after solder reflow. The standoff locations and surface area
located as specified in Appendix A. A minimum gap between the solder ball seating
plane and the standoff prior to reflow is required to prevent solder ball to motherboard
land open joints.
3.2.1.4 Markings
All markings 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 Section 5 without degrading.
3.2.1.4.1 Name
LGA771 (Font type is Helvetica Bold – minimum 6 point (or 2.125 mm)).
This mark shall be stamped or Laser Marked into the sidewall of the stiffener plate on
the actuation lever side when eutectic solder is used.
LF-LGA771 (Font type is Helvetica Bold – minimum 6 point (or 2.125 mm)).
This mark shall be stamped or Laser Marked into the sidewall of the stiffener plate on
the actuation lever side when lead-free solder is used.
Manufacturer’s insignia (Font size is at supplier’s discretion).
This mark will be molded or Laser Marked into the socket housing.
Both socket name and manufacturer’s insignia will be visible when first seated on the
motherboard.