Intel LGA 771 manual Introduction, Document Goals and Scope

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Introduction

1Introduction

1.1Document Goals and Scope

1.1.1LGA771 Socket Overview

This document describes a surface mount, LGA (Land Grid Array) socket intended for the Dual-Core Intel® Xeon® Processor 5000 Sequence Family for Servers and Workstations. The socket provides I/O, power and ground contacts. The socket contains 771 contacts arrayed about a cavity in the center of the socket with solder balls for surface mounting with the motherboard. The LF-LGA771 Socket contains lead- free solder balls while the LGA771 Socket contains eutectic solder balls. This Design Guide will refer to the socket as LGA771 for simplicity, but its contents are applicable to both lead-free and eutectic solder materials unless otherwise specified. The socket contacts have 1.09 mm X 1.17 mm pitch (X by Y) in a 33x30 grid array with 15x14 grid depopulation in the center of the array and selective depopulation for keying features. A matching LGA package will be mated with the socket.

For board layout, the land pattern for the LGA771 socket is 43 mils X 46 mils (X by Y), and the pad size is 18 mils. The component dimensions are defined in metric so there is a slight round-off error when converting to mils, but it is a negligible amount, relatively speaking, when compared to the size of the ball and pad. There have been no reported manufacturing issues.

1.1.2Document Goals

The goals of this document are:

•To provide LGA771 socket information necessary for motherboard design to ensure the specified performance of the platform.

•To define the boundary conditions and design constraints within which the socket design must fit and perform.

1.1.3Important Remarks

All LGA771 socket characteristics mentioned in this document may change.

LGA771 socket validation reports are available from socket vendors.

LGA 771 Socket Mechanical Design Guide

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Contents Mechanical Design Guide LGA771 SocketLGA 771 Socket Mechanical Design Guide Contents Tables FiguresRevision Description Date Revision HistoryLGA 771 Socket Mechanical Design Guide Document Goals and Scope IntroductionDocument Intel Order Number TerminologyReference Documents Term DescriptionAssembled Component and Package Description Assembled Component and Package Description Attachment Mechanical RequirementsSocket Components Name Package Installation / Removal AccessLot Traceability ContactsSocket Size Socket WeightPackage/Socket Stackup Height Socket Loading SpecificationsIntel Xeon 5000 Sequence Package and Socket Stackup Height Parameter Board Socket Loading SpecificationsMin Max Unit Thickness Definition of R Mechanical Requirements LGA771 Socket Electrical Requirements Electrical RequirementsCriteria Size Electrical Requirements Detailed description of this methodology can be found at Environmental RequirementsShipping and Handling Use Conditions EnvironmentDurability Solvent ResistanceEnvironmental Requirements Drawing Description Number Mechanical DrawingsFigure A-1. LGA Socket Assembly Drawing Sheet 1 Figure A-2. LGA Socket Assembly Drawing Sheet 2 Figure A-3. LGA Socket Assembly Drawing Sheet 3 Figure A-4. LGA Socket Assembly Drawing Sheet 4 Figure A-5. LGA771 Socket Motherboard Footprint Sheet 1 Figure A-6. LGA771 Socket Motherboard Footprint Sheet 2 Figure A-7. LGA771 Socket Motherboard Footprint Sheet 3 Figure A-8. LGA771 Socket Motherboard Footprint Sheet 4 Figure A-9. LGA771 Socket Motherboard Footprint Sheet 5 Figure A-10. LGA771 Socket Motherboard Footprint Sheet 6 Figure A-11. LGA 771 Socket Motherboard Footprint Sheet 7 Figure A-12. LGA 771 Socket Footprint Sheet 1 Figure A-13. LGA 771 Socket Footprint Sheet 2
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