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Intel Xeon E5-2400 Thermal/mechanical Design Manual

Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
May 2012
Reference Number: 327250-001
Legal Lines and Disclaimers
Intel may make changes to specifications and product descriptions at any time, without notice. Designers must not rely on the absence or characteristics of any features or instructions marked “reserved” or “undefined.” Intel
reserves these for future definition and shall have no responsibility whatsoev er for conflicts or incompatibilities arising from future changes to them.
The Intel® Xeon® E5-2400 Product Family may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request.
Requires a system with Intel® Turbo Boost Technology. Intel Turbo Boost Technology and Intel Turbo Boost Technology 2.0 are only available on select Intel® processors. Consult your PC manufacturer. Performance varies depending on hardware, software, and system configuration. For more information, visit http://www.intel.com/go/turbo
Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order. Copies of documents which have an order number and are referenced in this document, or other Intel literature may be obtained
by calling 1-800-548-4725 or by visiting Intel's website at http://www.intel.com. Intel, Xeon, and the Intel logo are tr ademarks or r egistered tr ad emarks of Intel Corpor ation or its subsidiaries in the United States
and other countries. *Other names and brands may be claimed as the property of others. Copyright © 2012, Intel Corporation. All Rights Reserved.
2 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
Contents
1Introduction..............................................................................................................9
1.1 References.......................................................................................................10
1.2 Definition of Terms............................................................................................10
2 LGA1356 Socket ......................................................................................................13
2.1 Board Layout....................................................................................................15
2.2 Attachment to Motherboard................................................................................16
2.3 Socket Components...........................................................................................16
2.3.1 Socket Body Housing..............................................................................16
2.3.2 Solder Balls...........................................................................................16
2.3.3 Contacts ...............................................................................................17
2.3.4 Pick and Place Cover...............................................................................17
2.4 Package Installation / Removal ......... ..................................................................18
2.4.1 Socket Standoffs and Package Seating Plane..............................................19
2.5 Durability.........................................................................................................19
2.6 Markings..........................................................................................................19
2.7 Component Insertion Forces ...............................................................................20
2.8 Socket Size ......................................................................................................20
2.9 LGA1356 Socket NCTF Solder Joints.....................................................................20
3 Independent Loading Mechanism (ILM) and Back Plate...........................................23
3.1 Design Concept.................................................................................................23
3.1.1 ILM Assembly Design Overview.............. .. .. ........................... .. ... ..............23
3.1.2 ILM Back Plate Design Overview...............................................................24
3.1.3 Durability..............................................................................................24
3.2 Assembly of ILM to a Motherboard.......................................................................25
3.3 ILM Cover .............. .. .. ......................... .. .......................... .. ......................... .. .. ..27
4 LGA1356 Socket, ILM and Back Plate Electrical, Mechanical, and Environmental
Specifications29
4.1 Component Mass...............................................................................................29
4.2 Package/Socket Stackup Height ..........................................................................29
4.3 Socket Maximum Temperature............................................................................29
4.4 Loading Specifications.................................... .. .. .. ......................... .. .. .................30
4.5 Electrical Requirements......................................................................................30
4.6 Environmental Requirements .................................................................. ............31
5Thermal Solutions...................................................................................................33
5.1 Boundary Conditions..........................................................................................33
5.2 Assembly .........................................................................................................35
5.2.1 Thermal Interface Material (TIM)..............................................................36
5.3 Structural Considerations ...................................................................................36
5.4 Thermal Design.................................................................................................36
5.4.1 Thermal Characterization Parameter.........................................................36
5.5 Fan Speed Control.............................................................................................37
5.5.1 Fundamentals........................................................................................37
5.6 Thermal Features..............................................................................................37
5.6.1 TCONTROL and DTS Relationship..............................................................38
5.6.2 Short Duration TCC Activation and Catastrophic Thermal
Management for Intel® Xeon® Processor E5-2400 Product Family....... ......... 39
5.6.3 Intel® Turbo Boost Technology................................................................40
5.7 Thermal Guidance .............................................................................................40
5.7.1 Thermal Excursion..................................................................................40
5.7.2 Absolute Processor Temperature ..............................................................40
Intel® Xeon® Processor E5-2400 Product Family 3 Thermal/Mechanical Design Guide
5.8 DTS Based Thermal Specification.........................................................................41
5.8.1 Compliance to Tcase Based Thermal Profile................................................41
5.8.2 Considerations for Follow-on Processor ......................................................41
5.8.3 DTS Based Thermal Profile, Tcontrol and Margin
for the Intel® Xeon® Processor E5-2400 Product Family .............................41
5.8.4 Power Calculation for the Intel® Xeon® Processor E5-2400 Product Family....42
5.8.5 Averaging the DTS Based Thermal Specification for the
5.8.6 Capabilities for the Follow-on Processor .....................................................43
6 Quality and Reliability Requirements .......................................................................45
6.1 Test Conditions .................................................................................................45
6.2 Intel Reference Component Validation ..................................................................45
6.2.1 Board Functional Test Sequence ...............................................................45
6.2.2 Post-Test Pass Criteria.............................................................................45
6.2.3 Recommended BIOS/Processor/Memory Test Procedures .............................46
6.3 Material and Recycling Requirements....................................................................46
A Component Su ppliers...............................................................................................47
A.1 Intel Enabled Supplier Information.......................................................................47
A.1.1 Intel Reference Thermal Solution..............................................................47
A.1.2 Intel Collaboration Thermal Solution..........................................................47
A.1.3 Alternative Thermal Solution ....................................................................48
A.1.4 Socket, ILM and Back Plate......................................................................50
B Mechanical Drawings ...............................................................................................51
C Socket Mechanical Drawings....................................................................................85
D Processor Installation Tool ......................................................................................91
E Embedded Thermal Solutions...................................................................................93
E.1 Performance Targets.................................................. ........................................93
E.2 Thermal Design Guidelines................................ .. ........................... .. ...................94
E.2.1 High Case Temperature Thermal Profile.....................................................94
E.3 Mechanical Drawings and Supplier Information......................................................95
Intel® Xeon® Processor E5-2400 Product Family........................................42
Figures
1-1 Intel® Xeon® Processor E5-2400 Product Family Platform Socket Stack ...... .. .. .. .. ...... 9
2-1 LGA1356 Socket with Pick and Place Cover Removed..............................................13
2-2 LGA1356 Socket Contact Numbering (Top View of Socket) ......................................14
2-3 LGA1356 Socket Land Pattern (Top View of Board).................................................15
2-4 Attachment to Motherboard................ .. .. ........................... ..................................16
2-5 Pick and Place Cover............................. .. .. ................................................... .. .. ..17
2-6 Package Installation / Removal Features...............................................................18
2-7 Package and Board Enabling Mark (-2) .................................................................19
2-8 LGA1356 NCTF Solder Joints ...............................................................................21
3-1 ILM Assembly....................................................................................................24
3-2 Back Plate ........................................................................................................25
3-3 ILM Assembly....................................................................................................26
3-4 Pin1 and ILM Lever ............................................................................................27
4-1 Flow Chart of Knowledge-Based Reliability Evaluation Methodology...........................32
5-1 Best-fit Equations ..............................................................................................34
5-2 1U Reference Heatsink Assembly .........................................................................35
5-3 Processor Thermal Characterization Parameter Relationships ...................................37
B-1 Board Keepin / Keep out Zone s (She et 1 of 4)................................... .. .. .. ...............52
4 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
B-2 Board Keepin / Keepout Zones (Sheet 2 of 4)........................................................53
B-3 Board Keepin / Keepout Zones (Sheet 3 of 4)........................................................54
B-4 Board Keepin / Keepout Zones (Sheet 4 of 4)........................................................55
B-5 1U Reference Heatsink Assembly (Sheet 1 of 2) ....................................................56
B-6 1U Reference Heatsink Assembly (Sheet 2 of 2) ....................................................57
B-7 1U Reference Heatsink Fin and Base (Sheet 1 of 2)................................................58
B-8 1U Reference Heatsink Fin and Base (Sheet 2 of 2)................................................59
B-9 Heatsink Shoulder Screw (1U, 2U and Tower) .......................................................60
B-10 Heatsink Compression Spring (1U, 2U and Tower).................................................61
B-11 Heatsink Retaining Ring (1U, 2U and Tower).........................................................62
B-12 Heatsink Load Cup (1U, 2U and Tower)................................................................63
B-13 2U Collaborative Heatsink Assembly (Sheet 1 of 2)................................................64
B-14 2U Collaborative Heatsink Assembly (Sheet 2 of 2)................................................65
B-15 2U Collaborative Heatsink Volumetric (Sheet 1 of 2) ......................... .. .. .................66
B-16 2U Collaborative Heatsink Volumetric (Sheet 2 of 2) ......................... .. .. .................67
B-17 Tower Collaborative Heatsink Assembly (Sheet 1 of 2) ...........................................68
B-18 Tower Collaborative Heatsink Assembly (Sheet 2 of 2) ...........................................69
B-19 Tower Collaborative Heatsink Volumetric (Sheet 1 of 2)..........................................70
B-20 Tower Collaborative Heatsink Volumetric (Sheet 2 of 2)..........................................71
B-21 1U Reference Heatsink Assembly with TIM (Sheet 1 of 2) .......................................72
B-22 1U Reference Heatsink Assembly with TIM (Sheet 2 of 2) .......................................73
B-23 2U Reference Heatsink Assembly with TIM (Sheet 1 of 2) .......................................74
B-24 2U Reference Heatsink Assembly with TIM (Sheet 2 of 2) .......................................75
B-25 Tower Reference Heatsink Assembly with TIM (Sheet 1 of 2)...................................76
B-26 Tower Reference Heatsink Assembly with TIM (Sheet 2 of 2)...................................77
B-27 25.5 mm Reference Heatsink Assembly (Sheet 1 of 2) ...........................................78
B-28 25.5 mm Reference Heatsink Assembly (Sheet 2 of 2) ...........................................79
B-29 25.5 mm Reference Heatsink Fin and Base (Sheet 1 of 2).......................................80
B-30 25.5 mm Reference Heatsink Fin and Base (Sheet 2 of 2).......................................81
B-31 25.5 mm Reference Heatsink Assembly with TIM (Sheet 1 of 2)...............................82
B-32 25.5 mm Reference Heatsink Assembly with TIM (Sheet 2 of 2)...............................83
C-1 Socket Mechanical Drawing (Sheet 1 of 4)............................................................86
C-2 Socket Mechanical Drawing (Sheet 2 of 4)............................................................87
C-3 Socket Mechanical Drawing (Sheet 3 of 4)............................................................88
C-4 Socket Mechanical Drawing (Sheet 4 of 4)............................................................89
D-1 Processor Installation Tool..................................................................................92
E-1 ATCA Heatsink Performance Curves.............................................. .......................94
E-2 NEBS Thermal Profile.........................................................................................95
E-3 ATCA Reference Heat Sink Assembly (Sheet 1 of 2) ...............................................97
E-4 ATCA Reference Heat Sink Assembly (Sheet 2 of 2) ...............................................98
E-5 ATCA Reference Heatsink Fin and Base (Sheet 1 of 2)............................................99
E-6 ATCA Reference Heatsink Fin and Base (Sheet 2 of 2).......................................... 100
Tables
1-1 Reference Documents..................................................................... .. .................10
1-2 Terms and Descriptions......................................................................................10
4-1 Component Mass...............................................................................................29
4-2 1356-land Package and LGA1356 Socket Stackup Height........................................29
4-3 Socket and ILM Mechanical Specifications.............................................................30
4-4 Electrical Requirements for LGA1356 Socket ......................................................... 31
5-1 Values Used to Generate Processor Thermal Specifications......................................33
5-2 Performance Expectations in Compact Electronics Bay (CEB)................................... 34
Intel® Xeon® Processor E5-2400 Product Family 5 Thermal/Mechanical Design Guide
5-3 TCONTROL and DTS Relationship.........................................................................38
5-4 Sign Convention................................................................................................38
5-5 T
CONTROL
Relief for Intel® Xeon® Processor E5-2400 Product Family........................39
5-6 Averaging Coefficients........................................................................................43
A-1 Suppliers for the Intel Reference Thermal Solution.................................................47
A-2 Suppliers for the Intel Collaboration Thermal Solution.............................................48
A-3 Suppliers for the Alternative Thermal Solution .......................................................48
A-4 LGA135 6 Socket, ILM and Back Plate........................................................ ............50
B-1 Mechanical Drawing List......................................................................................51
C-1 Mechanical Drawing List......................................................................................85
E-1 8-Core/6-Core Processor Reference Thermal Boundary Conditions............................93
E-2 4-Core Processor Reference Thermal Boundary Conditions.......................................93
E-3 Embedded Heatsink Component Suppliers.............................................................95
E-4 Mechanical Drawings List....................................................................................96
6 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
Revision History
Document
Number
327250 -001 • Initial release of the document. May 2012
Revision
Number
Description Date
§
Intel® Xeon® Processor E5-2400 Product Family 7 Thermal/Mechanical Design Guide
8 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
Introduction

1 Introduction

This document provides guidelines for the design of thermal and mechanical solutions for server and workstation processors in the Intel® Xeon® Processor E5-2400 Product Family platform. The processors covered include those listed in the Intel® Xeon® Processor E5-2400 Product Family Datasheet - Volume One. The components described in this document include:
• The processor thermal solution (heatsink) and associated retention hardware.
• The LGA1356 socket, the Independent Loading Mechanism (ILM) and back plate.
Figure 1-1. Intel® Xeon® Processor E5-2400 Product Family Platform Socket Stack
The goals of this document are:
• To assist board and system thermal mechanical designers.
• To assist designers and suppliers of processor heatsinks.
Thermal profiles and other processor specifications are provided in the appropriate Datasheet.
Intel® Xeon® Processor E5-2400 Product Family 9 Thermal/Mechanical Design Guide

1.1 References

Material and concepts available in the following documents may be beneficial when reading this document.
Table 1-1. Reference Documents
Document Number Notes
European Blue Angel Recycling Standards 2 Intel® Xeon® Processor E5-2400 Product Family Datasheet -
Volume One Platform Environment Control Interface (PECI) Specification 4 Intel® Xeon® Processor E5-2400 Processor Product Family
Mechanical Model Intel® Xeon® Processor E5-2400 Processor Product Family
Thermal Model Manufacturing With Intel Components Using Lead-Free
Technology Platform Digital Thermal Sensor (DTS) Based Thermal
Specifications and Overview
Notes:
1. Available at http://www.intel.com. Document numbers are subject to change.
2. Available at http://www.blauer-engel.de/en/index.php
3. Available at https://learn.intel.com/portal/scripts/general/logon.aspx.
4. Contact your local Intel Field Sales Representative.
Introduction
327248 1
327322 1
327321 1
3
4

1.2 Definition of Terms

Table 1-2. Terms and Descriptions (Sheet 1 of 2)
Term Description
Bypass Bypass is the area between a passive heatsink and any object that can act to form a
DTS Digital Thermal Sensor reports a relative die temperature as an offset from TCC
FSC Fan Speed Control IHS Integrated Heat Spreader: a component of the processor pac k age used to enhance the
ILM Independent Loading Mechanism provides the force needed to seat the 1356-LGA land
LGA1356 socket The processor mates with the system board through this surface mount, 1356-contact
PECI The Platform Environment Control Interface (PECI) is a one- wire in terface that pro vides
Ψ
CA
Ψ
CS
Ψ
SA
duct. For this example, it can be expressed as a dimension away from the outside dimension of the fins to the nearest surface.
activation temperature.
thermal performance of the package. Component thermal solutions interface with the processor at the IHS surface.
package onto the socket contacts.
socket.
a communication channel between Intel processor and chipset components to external monitoring devices.
Case-to-ambient thermal characterization parameter (psi). A measure of thermal solution performance using t otal package power. Defined as (T Package Power. Heat source should always be specified for Ψ measurements.
Case-to-sink thermal characterization parameter. A measure of thermal interface material performance using total package po wer. Defined as (T Package Power.
Sink-to-ambient thermal characterization parameter. A measure of heatsink thermal performance using total package power. Defined as (T
– TLA) / Total
CASE
– TS) / Total
CASE
– TLA) / Total Package Power.
S
10 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
Introduction
Table 1-2. Terms and Descriptions (Sheet 2 of 2)
Term Description
T
CASE
T
CASE_MAX
TCC Thermal Control Circuit: Thermal monitor uses the TCC to reduce the die temperature
T
CONTROL
TDP Thermal Design Power: Thermal solution should be designed to dissipate this target
Thermal Monitor A power reduction feature designed to decrease temperature after the processor has
Thermal Profile Line that defines the temperature specification of a processor at a given power level. TIM Thermal Interface Material: The thermally conductive compound between the heatsink
T
LA
T
SA
U A unit of measure used to define server rack spacing height. 1U is equal to 1.75 in, 2U
The case temperature of the p rocessor measure d at the geomet ric center of the topside of the IHS.
The maximum case temperature as specified in a component specification.
by using clock modulation and/or operating frequency and input voltage adjustment when the die temperature is very near its operating limits.
T control.
is a static value below TCC activation used as a trigger point for fan speed
CONTROL
power level. TDP is not the maximum power that the processor can dissipate.
reached its maximum operating temperature.
and the processor case. This material fills the air gaps and voids, and enhances the transfer of the heat from the processor case to the heatsink.
The measured ambient temperature locally surrounding the proces sor. The ambient temperature should be measured just upstream of a p assive he atsink or at the fan inle t for an active heatsink.
The system ambient air temperature external to a system chassis. This temperature is usually measured at the chassis air inlets.
equals 3.50 in, etc.
§
Intel® Xeon® Processor E5-2400 Product Family 11 Thermal/Mechanical Design Guide
Introduction
12 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
LGA1356 Socket

2 LGA1356 Socket

This chapter describes a surface mount, LGA (Land Grid Array) socket intended for processors in the E5-2400 Product Family Platform. The socket provides I/O , power and ground contacts. The socket contains 1356 contacts arrayed about a cavity in the center of the socket with lead-free solder balls for surface mounting on the motherboard.
The socket has 1356 contacts with 1.016 mm X 1.016 mm pitch (X by Y) in a 43x41 grid array with 21x17 grid depopulation in the center of the array and selective depopulation elsewhere.
The socket must be compatible with the package (processor) and the Independent Loading Mechanism (ILM). The design includes a back plate which is a key contributor in producing a uniform load on the socket solder joints. Socket loading specifications are listed in Section 4.4.
Figure 2-1. LGA1356 Socket with Pick and Place Cover Removed
Intel® Xeon® Processor E5-2400 Product Family 13 Thermal/Mechanical Design Guide
Figure 2-2. LGA1356 Socket Contact Numbering (Top View of Socket)
LGA1356 Socket
14 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
LGA1356 Socket

2.1 Board Layout

The land pattern for the LGA1356 socket is 40 mils X 40 mils (X by Y). Note that there is no round-off (conversion) error between socket pitch (1.016 mm) and board pitch (40 mil) as these values are equivalent.
In general, metal defined (MD) pads perform better than solder mask defined (SMD) pads under thermal cycling, and SMD pads perform better than MD pads under dynamic stress. At this time, complete recommendations for pad definition and pad size do not exist for the LGA1356 socket. See Section 2.9 for more information on pad definition and pad size.
Figure 2-3. LGA1356 Socket Land Pattern (Top View of Board)
Intel® Xeon® Processor E5-2400 Product Family 15 Thermal/Mechanical Design Guide

2.2 Attachment to Motherboard

LGA1356
Socket
ILM
The socket is attached to the motherboard by 1356 solder balls. There are no additional external methods (that is, screw, extra solder, adhesive, and so on) to attach the socket.
As indicated in Figure 2-4, the Independent Loading Mechanism (ILM) is not present during the attach (reflow) process.
Figure 2-4. Attachment to Motherboard
LGA1356 Socket

2.3 Socket Components

The socket has two main components, the socket body and Pick and Place (PnP) cover, and is delivered as a single integral assembly. Refer to Appendix C for detailed drawings.

2.3.1 Socket Body Housing

The housing material is thermoplastic or equivalent with UL 94 V -0 flame rating capable of withstanding 260 °C for 40 seconds (typical reflow/rework). The socket coefficient of thermal expansion (in the XY plane), and creep properties, must be such that the integrity of the socket is maintained for the conditions listed in the LGA1366 Socket Validation Reports, and the LGA1356 Addendum.
The color of the housing will be dark as compared to the solder balls to provide the contrast needed for pick and place vision systems.

2.3.2 Solder Balls

A total of 1356 solder balls corresponding to the contacts are on the bottom of the socket for surface mounting with the motherboard.
The socket has the following solder ball material:
• Lead free SAC (SnAgCu) solder alloy with a silver (Ag) content between 3% and 4% and a melting temperature of approximately 217 °C. The alloy must be
16 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
LGA1356 Socket
ILM Installation
Pick and Place Cover
Pin 1
ILM cover
compatible with immersion silver (ImAg) motherboard surface finish and a SAC alloy solder paste.
The co-planarity (profile) and true position requirements are defined in Appendix C.

2.3.3 Contacts

Base material for the contacts is high strength copper alloy. For the area on socket contacts where processor lands will mate, there is a 0.381 μm
[15 μinches] minimum gold plating over 1.27 μm [50 μinches] minimum nickel underplate.
No contamination by solder in the contact area is allowed during solder reflow.

2.3.4 Pick and Place Cover

The cover provides a planar surface for vacuum pick up used to place components in the Surface Mount Technology (SMT) manufacturing line. The cover remains on the socket during reflow to help prevent contamination during reflow. The cover can withstand 260 °C for 40 seconds (typical reflow/rework profile) and the conditions listed in the LGA1366 Socket Validation Reports, and LGA1356 Addendum, without degrading. Reports are available from socket suppliers listed in Appendix A.
As indicated in Figure 2-5, the Pick and Place cover remains on the socket during ILM installation. Use of the ILM cover can mitigate against bent socket contacts associated with reinstalling the Pick and Place cover. A cover should remain on whenever possible to help prevent damage to the socket contacts. See Section 3.2 and Section 3.3 for additional information on the ILM cover.
Pick and Place cover retention must be sufficient to support the socket weight during lifting, translation, and placement (board manufacturing), and during board and system shipping and handling.
Pick and Place covers are designed to be interchangeable between socket suppliers. As indicated in Figure 2-5, a Pin1 indicator on the Pick and Place cover provides a visual reference for proper orientation with the socket.
Figure 2-5. Pick and Place Cover
Intel® Xeon® Processor E5-2400 Product Family 17 Thermal/Mechanical Design Guide

2.4 Package Installation / Removal

As indicated in Figure 2-6, access is provided to facilitate manual installation and removal of the package.
To assist in package orientation and alignment with the socket:
• The package Pin1 triangle and the socket Pin1 chamfer provide visual reference for proper orientation.
• The package substrate has orientation notches along two opposing edges of the package, offset from the centerline. The socket has two corresponding orientation posts to physically prevent mis-orientation of the package. These orientation features also provide initial rough alignment of package to socket.
• As shown in Figure 2-7, the package substrate has a “-2” mark near the orientation notch on the Pin 1 side. Similarly, space has been reserved for a “-2” mark on the motherboard in the Board Keepin / Keepout Z on es in Figure B-1 and Figure B-2. These matching marks help prevent system assemblers from installing the incorrect processor into the socket.
• The socket has alignment walls at the four corners to provide final alignment of the package.
See Appendix D for information regarding a tool designed to provide mechanical
.
Figure 2-6. Package Installation / Removal Features
assistance during processor installation and removal.
LGA1356 Socket
18 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
LGA1356 Socket
Figure 2-7. Package and Board Enabling Mark (-2)

2.4.1 Socket Standoffs and Package Seating Plane

Standoffs on the bottom of the socket base establish the minimum socket height after solder reflow and are specified in Appendix C.
Similarly, a seating plane on the topside of the socket establishes the minimum package height. See Section 3.2 for the calculated IHS height above the motherboard.

2.5 Durability

The socket must withstand 30 cycles of processor insertion and removal. The max chain contact resistance from Table 4-4 must be met when mated in the 1st and 30th cycles.
The socket Pick and Place cover must withstand 15 cycles of insertion and removal.

2.6 Markings

There are three markings on the socket:
• LGA1356: Font type is Helvetica Bold - minimum 6 point (2.125 mm).
• Manufacturer's insignia (font size at supplier's discretion).
• Lot identification code (allows traceability of manufacturing date and location).
All markings must withstand 260 °C for 40 seconds (typical reflow/rework profile) without degrading, and must be visible after the socket is mounted on the motherboard.
LGA1356 and the manufacturer's insignia are molded or laser marked on the side wall.
Intel® Xeon® Processor E5-2400 Product Family 19 Thermal/Mechanical Design Guide

2.7 Component Insertion Forces

Any actuation must meet or exceed SEMI S8-95 Safety Guidelines for Ergonomics/ Human Factors Engineering of Semiconductor Manufacturing Equipment, example T able R2-7 (Maximum Grip Forces). The socket must be designed so that it requires no force to insert the package into the socket.

2.8 Socket Size

Socket information needed for motherboard design is given in Appendix C. This information should be used in conjunction with the reference motherboard keepout
drawings provided in Appendix B to ensure compatibility with the reference thermal mechanical components.

2.9 LGA1356 Socket NCTF Solder Joints

Intel has defined selected solder joints of the socket as non-critical to function (NCTF) for post environmental testing. The processor signals at NCTF locations are typically redundant ground or non-critical reserved, so the loss of the solder joint continuity at end of life conditions will not affect the overall product functionality. Figure 2-8 identifies the NCTF solder joints.
LGA1356 Socket
Since corner pads are often more susceptible to solder joint damage, NCTF locations are often placed in the corners. When possible, larger pads may be chosen at NCTF locations to further mitigate against solder joint damage. At this time, complete recommendations for pad definition and pad size do not exist at NCTF locations. CTF and NCTF locations are 18mil solder mask defined on Intel reference designs.
20 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide
LGA1356 Socket
.
Figure 2-8. LGA1356 NCTF Solder Joints
§
Intel® Xeon® Processor E5-2400 Product Family 21 Thermal/Mechanical Design Guide
LGA1356 Socket
22 Intel® Xeon® Processor E5-2400 Product Family
Thermal/Mechanical Design Guide

Independent Loading Mechanism (ILM) and Back Plate

3 Independent Loading
Mechanism (ILM) and Back Plate
The Independent Loading Mechanism (ILM) provides the force needed to seat the 1356-LGA land package onto the socket contacts. The ILM is physically separate from the socket body. The assembly of the ILM to the board is expected to occur after wave solder. The exact assembly location is dependent on manufacturing preference and test flow.
Note: The ILM has two critical functions: deliver the force to seat the processor onto the
socket contacts and distribute the resulting compressive load evenly through the socket solder joints.
Note: The mechanical design of the ILM is a key contributor to the over all fun ctionality of the
LGA1356 socket. Intel performs detailed studies on integration of processor package, socket and ILM as a system. These studies directly impact the design of the ILM. The Intel reference ILM will be “build to print” from Intel controlled drawings. Intel recommends using the Intel Reference ILM. Custom non-Intel ILM designs do not benefit from Intel's detailed studies and may not incorporate critical design parameters.

3.1 Design Concept

The ILM and back plate are assemblies and can be procured from the enabled vendors.

3.1.1 ILM Assembly Design Overview

The ILM assembly consists of four major pieces: load lever, load plate, frame and the captive fasteners.
The load lever and load plate are stainless steel. The frame and fasteners are high carbon steel with appropriate plating. The fasteners are fabricated from a high carbon steel. The frame provides the hinge locations for the load lever and load plate.
The ILM assembly design ensures that once assembled to the back plate and the load lever is closed, the only features touching the board are the captive fasteners. The nominal gap of the frame to the board is ~1 mm when the load plate is closed on the empty socket or when closed on the processor package.
When closed, the load plate applies two point loads onto the IHS at the “dimpled” features shown in Figure 3-1. The reaction force from closing the load plate is transmitted to the frame and through the captive fasteners to the back plate. Some of the load is passed through the socket body to the board inducing a slight compression on the solder joints.
Intel® Xeon® Processor E5-2400 Product Family 23 Thermal/Mechanical Design Guide
Figure 3-1. ILM Assembly
Independent Loading Mechanism (ILM) and Back Plate

3.1.2 ILM Back Plate Design Overview

The unified back plate consists of a flat steel back plate with threaded studs for ILM attach, and internally threaded nuts for heatsink attach. The threaded studs have a smooth surface feature that provides alignment for the back plate to the motherboard for proper assembly of the ILM around the socket. A clearance hole is located at the center of the plate to allow access to test points and backside capacitors. An additional cut-out on two sides provides clearance for backside voltage regulator components. An insulator is pre-applied. To stay within the temperature limit of the insulator, remove the back plate prior to board component rework.

3.1.3 Durability

The ILM durability requirement is 30 processor cycles. 1 processor cycle = install processor, close load plate, latch load lever, unlatch load lever, open load plate.
The ILM durability requirement is 6 assembly cycles. See Section 3.2 for assembly procedure. 1 assembly cycle = fasten the ILM assembly to the back plate with the four captive screws, torque to 9 ± 1 inch-pounds, unfasten ILM assembly from the back plate.
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Figure 3-2. Back Plate

3.2 Assembly of ILM to a Motherboard

The ILM design allows a bottoms up assembly of the components to the board. In step 1 (see Figure 3-3), the back plate is placed in a fixture. Holes in the motherboard provide alignment to the threaded studs.
In step 2, the ILM assembly is placed over the socket and threaded studs. The Intel Reference Design ILM cover is not designed to nest over the Pick and Place cover. This feature helps prevent reinstallation of the Pick and Place cover, a step that can lead to socket bent contacts.
To prevent the ILM cover from popping off during ILM assembly, the load plate can be unlatched from the load lever when the fasteners are torqued as shown is Step 3. Using a T20 Torx* driver, fasten the ILM assembly to the back plate with the four captive fasteners. Torque to 9 ± 1 inch-pounds.
The Pick and Place cover can then be removed as shown in Step 4, and the load plate can then closed and latched as shown in Step5.
The length of the threaded studs accommodate board thicknesses from
0.062” to 0.100”.
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.
ILM co ver
Step 1: With socket body reflowed on board, and back plate in fixture, align board holes to back plate studs.
Step 2: With back plate against bottom of board, align ILM assembly to back plate studs.
ILM cover
Pick and Place Cover
Step 3
Step 4 Step 5
Figure 3-3. ILM Assembly
Independent Loading Mechanism (ILM) and Back Plate
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As indicated in Figure 3-4, socket protrusion and ILM key features prevent 180-degree rotation of ILM assembly with respect to the socket. The result is a specific Pin 1 orientation with respect to the ILM lever.
Figure 3-4. Pin1 and ILM Lever

3.3 ILM Cover

As indicated in Table A-4, ILM covers are available as discrete components and pre­assembled to the ILM load plate.
The ILM cover will interfere with a processor and pop off if the ILM is closed with a processor in the socket.
The ILM cover is designed to be interchangeable between different suppliers validated by Intel. Performance of the pop off feature may decline if the ILM cover supplier is different than the ILM supplier. The ILM cover can be removed manually if the pop off feature is not desirable, or not functional.
The ILM cover has UL94 V-0 flammability rating. The ILM cover durability requirement is 20 cycles (1 cycle = install and remove).
§
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LGA1356 Socket, ILM and Back Plate Electrical, Mechanical, and Environmental Specifications

4 LGA1356 Socket, ILM and Back
Plate Electrical, Mechanical, and Environmental Specifications
This chapter describes the electrical, mechanical, and environmental specifications for the LGA1356 socket, Independent Loading Mechanism and Back Plate.

4.1 Component Mass

Table 4-1. Component Mass
Component Mass
Socket Body, Contacts and PnP Cover 15 gm ILM Assembly 43 gm Back Plate 100 gm

4.2 Package/Socket Stackup Height

Table 4-2 provides the stackup height of a processor in the 1356-land LGA package and
LGA1356 socket with the ILM closed and the processor fully seated in the socket.
Table 4-2. 1356-land Package and LGA1356 Socket Stackup Height
Integrated Stackup Height (mm) From Top of Board to Top of IHS
Notes:
1. This data is provided for information only, and is derived from: (a) the height of the socket seating plane above the motherboard after reflow, given in Appendix C, (b) the height of the packag e, fr om the pac kage seating plane to the top of the IHS, and accounting for its nominal variation and tolerances that are given in the corresponding processor EDS and expected values for the follow-on processor.
2. This value is a RSS calculation.
7.753 ± 0.262 mm

4.3 Socket Maximum Temperature

The power dissipated within the socket is a function of the current at the pin level and the effective pin resistance. To ensure socket long term reliability, Intel defines socket maximum temperature using a via on the underside of the motherboard. Exceeding the temperature guidance may result in socket body deformation, or increases in thermal and electrical resistance which can cause a thermal runaway and eventual electrical failure. The guidance for socket maximum temperature is listed below:
• Via temperature under socket < 96 °C
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LGA1356 Socket, ILM and Back Plate Electrical, Mechanical, and Environmental Specifications

4.4 Loading Specifications

The socket will be tested against the conditions listed in the LGA1366 Socket Validation Reports, and LGA1356 Addendum, with heatsink, ILM and back plate attached, under the loading conditions outlined in this chapter.
Table 4-3 provides load specifications for the LGA1356 socket with the ILM and back
plate installed. The maximum limits should not be exceeded during heatsink assembly, shipping conditions, or standard use condition. Exceeding these limits during test may result in component failure. The socket body should not be used as a mechanical reference or load-bearing surface for thermal solutions.
Table 4-3. Socket and ILM Mechanical Specifications
Parameter Min Max Notes
Static compressive load from ILM to processor IHS
Thermal Solution Static Compressive Load 0 N [0 lbf] 266 N [60 lbf] 1, 2, 3 Total Static Compressive Load
(ILM plus Heatsink) Dynamic Compressive Load
(with heatsink installed) Target Pick and Place Cover allowable removal
force Load Lever actuation force N/A 38.3 N [8.6 lbf] in the
445 N [100 lbf] 623 N [140 lbf] 3, 4
445 N (100 lbf) 890 N (200 lbf) 3, 4
N/A 890 N [200 lbf] 1, 3, 5, 6
N/A 4.45 - 6.68 N [1.0 -
1.5 lbf]
vertical direction
10.2 N [2.3 lbf] in the lateral direction.
Notes:
1. These specifications apply to uniform compressive loading in a direction perpendicular to the IHS top surface.
2. This is the minimum and maximum static force that can be applied by the heatsink and it’s retention solution to maintain the heatsink to IHS interface. This does not imply the Intel reference TIM is validated to these limits. TIM load range is documented in Section 5.2 for the Intel Reference Design.
3. Loading limits are for the LGA1356 socket.
4. This minimum limit defines th e compressi ve forc e required to electrically seat the processor onto the sock et contacts.
5. Dynamic loading is defined as an 11 ms duration average load superimposed on the static load requirement.
6. T est condition used a heatsink mass of 550 gm [1.21 lb] with 50 g acceler ation measured at heatsi nk mass. The dynamic portion of this specification in the product application can have flexibility in specific values, but the ultimate product of mass times acceleration should not exceed this dynamic load.

4.5 Electrical Requirements

LGA1356 socket electrical requirements are measured from the socket-seating plane of the processor to the component side of the socket PCB to which it is attached. All specifications are maximum values (unless otherwise stated) for a single socket contact, but includes effects of adjacent contacts where indicated.
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