Intel BX80616I3540, Xeon 3500 Series Design Manual
Intel® Xeon® Processor 3500 Series
Thermal / Mechanical Design Guide
March 2009
Document Number: 321461-001
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Copyright © 2009, Intel Corporation.
2 Thermal and Mechanical Design Guide
Contents
1Introduction..............................................................................................................7
1.1 References.........................................................................................................8
1.2 Definition of Terms..............................................................................................8
2 LGA1366 Socket ......................................................................................................11
2.1 Board Layout....................................................................................................13
2.2 Attachment to Motherboard................................................................................14
2.3 Socket Components...........................................................................................14
2.3.1 Socket Body Housing..............................................................................14
2.3.2 Solder Balls...........................................................................................14
2.3.3 Contacts ...............................................................................................15
2.3.4 Pick and Place Cover...............................................................................15
2.4 Package Installation / Removal ......... ..................................................................16
2.4.1 Socket Standoffs and Package Seating Plane..............................................16
2.5 Durability.........................................................................................................17
2.6 Markings..........................................................................................................17
2.7 Component Insertion Forces ...............................................................................17
2.8 Socket Size ......................................................................................................17
2.9 LGA1366 Socket NCTF Solder Joints.....................................................................18
3 Independent Loading Mechanism (ILM)...................................................................19
3.1 Design Concept.................................................................................................19
3.1.1 ILM Cover Assembly Design Overview.......................................................19
3.1.2 ILM Back Plate Design Overview...............................................................20
3.2 Assembly of ILM to a Motherboard.......................................................................20
4 LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications .23
4.1 Component Mass...............................................................................................23
4.2 Package/Socket Stackup Height ..........................................................................23
4.3 Socket Maximum Temperature............................................................................23
4.4 Loading Specifications.................................... .. .. .. ......................... .. .. .................24
4.5 Electrical Requirements......................................................................................24
4.6 Environmental Requirements .................................................................. ............25
5 Sensor Based Thermal Specification Design Guidance..............................................27
5.1 Sensor Based Specification Overview...................................................................27
5.2 Sensor Based Thermal Specification.....................................................................28
5.2.1 TTV Thermal Profile................................................................................28
5.2.2 Specification When DTS value is Greater than TCONTROL ............................29
5.3 Thermal Solution Design Process.........................................................................30
5.3.1 Boundary Condition Definition..................................................................30
5.3.2 Thermal Design and Modelling.................................................................. 31
5.3.3 Thermal Solution Validation.....................................................................32
5.4 Fan Speed Control (FSC) Design Process..............................................................33
5.4.1 Fan Speed Control Algorithm without TAMBIENT Data .................................34
5.4.2 Fan Speed Control Algorithm with TAMBIENT Data......................................35
5.5 System Validation .............................................................................................36
5.6 Specification for Operation Where Digital Thermal Sensor Exceeds TCONTROL.... .......37
6 ATX Reference Thermal Solution..............................................................................39
6.1 Operating Environment............................... ... .. .. ................................................39
6.2 Heatsink Thermal Solution Assembly....................................................................40
6.3 Geometric Envelope for the Intel
6.4 Reference Design Components................................................... .. .. .....................42
®
Reference ATX Thermal Mechanical Design ...........41
Thermal and Mechanical Design Guide 3
6.4.1 Extrusion...............................................................................................42
6.4.2 Clip.......................................................................................................43
6.4.3 Core .....................................................................................................44
6.5 Mechanical Interface to the Reference Attach Mechanism ........................................44
6.6 Heatsink Mass and Center of Gravity....................................................................46
6.7 Thermal Interface Material.............................................................................. .. ..46
6.8 Absolute Processor Temperature..........................................................................46
7 Thermal Solution Quality and Reliability Requirements ............................................47
7.1 Reference Heatsink Thermal Verification ...............................................................47
7.2 Mechanical Environmental Testing........................................................................47
7.2.1 Recommended Test Sequence ..................................................................47
7.2.2 Post-Test Pass Criteria.............................................................................48
7.2.3 Recommended BIOS/Processor/Memory Test Procedures .............................48
7.3 Material and Recycling Requirements....................................................................48
A Component Suppliers...............................................................................................49
B Mechanical Drawings ...............................................................................................51
C Socket Mechanical Drawings....................................................................................65
D Processor Installation Tool ......................................................................................71
Figures
1-1 Processor Thermal Solution & LGA1366 Socket Stack.................................................... 7
2-1 LGA1366 Socket with Pick and Place Cover Removed ......................................... .. ........11
2-2 LGA1366 Socket Contact Numbering (Top View of Socket)............................................12
2-3 LGA1366 Socket Land Pattern (Top View of Board) ......................................................13
2-4 Attachment to Motherboard.................................................... ... .. ........................... ..14
2-5 Pick and Place Cover................................................................................................15
2-6 Package Installation / Removal Features .... ................................................................16
2-7 LGA1366 NCTF Solder Joints.....................................................................................18
3-1 ILM Cover Assembly................................................................................................20
3-2 ILM Assembly.........................................................................................................21
3-3 Pin1 and ILM Lever..................................................................................................22
4-1 Flow Chart of Knowledge-Based Reliability Evaluation Methodology ................................26
5-1 Comparison of Case Temperature vs. Sensor Based Specification...................................28
5-2 Thermal Profile ..................... .. ........................... ... .. ........................... .. .. .. ...............29
5-3 Thermal solution Performance...................................................................................30
5-4 Required YCA for various TAMBIENT Conditions...................................... .. ...................31
5-5 Thermal Solution Performance vs. Fan Speed..............................................................33
5-6 Fan Response Without TAMBIENT Data.......................................................................34
5-7 Fan Response with TAMBIENT Aware FSC...................................................................35
6-1 ATX Heatsink Reference Design Assembly...................................................................40
6-2 ATX KOZ 3-D Model Primary (Top) Side......................................................................41
6-3 RCBF5 Extrusion .....................................................................................................42
6-4 RCBF5 Clip.............................................................................................................43
6-5 Core......................................................................................................................44
6-6 Clip Core and Extrusion Assembly..............................................................................45
6-7 Critical Parameters for Interface to the Reference Clip..................................................45
6-8 Critical Core Dimensions ..........................................................................................46
B-1 Socket / Heatsink / ILM Keepout Zone Primary Side (Top)............................................52
B-2 Socket / Heatsink / ILM Keepout Zone Secondary Side (Bottom) ...................................53
B-3 Socket / Processor / ILM Keepout Zone Primary Side (Top)...........................................54
B-4 Socket / Processor / ILM Keepout Zone Secondary Side (Bottom)..................................55
B-5 Reference Design Heatsink Assembly (1 of 2)..............................................................56
4 Thermal and Mechanical Design Guide
B-6 Reference Design Heatsink Assembly (2 of 2).............................................................57
B-7 Reference Fastener Sheet 1 of 4...............................................................................58
B-8 Reference Fastener Sheet 2 of 4...............................................................................59
B-9 Reference Fastener Sheet 3 of 4...............................................................................60
B-10 Reference Fastener Sheet 4 of 4 ...............................................................................61
B-11 Reference Clip - Sheet 1 of 2.......................................... ............................ .. ............62
B-12 Reference Clip - Sheet 2 of 2.......................................... ............................ .. ............63
C-1 Socket Mechanical Drawing (Sheet 1 of 4)..................................................................66
C-2 Socket Mechanical Drawing (Sheet 2 of 4)..................................................................67
C-3 Socket Mechanical Drawing (Sheet 3 of 4)..................................................................68
C-4 Socket Mechanical Drawing (Sheet 4 of 4)..................................................................69
D-1 Processor Installation Tool .......................................................................................72
Tables
1-1 Reference Documents.................................................................................................8
1-2 Terms and Descriptions ..............................................................................................8
4-1 Socket Component Mass................................ .. ............................ ........................... ..23
4-2 1366-land Package and LGA1366 Socket Stackup Height............................................... 23
4-3 Socket and ILM Mechanical Specifications....................................................................24
4-4 Electrical Requirements for LGA1366 Socket................................................................25
5-1 Thermal Solution Performance above TCONTROL..........................................................37
6-1 Processor Thermal Solution Requirements & Boundary Conditions...................................39
7-1 Use Conditions (Board Level).....................................................................................47
A-1 Reference Heatsink Enabled Components....................................................................49
A-2 LGA1366 Socket and ILM Components........................................................................49
A-3 Supplier Contact Information.....................................................................................49
B-1 Mechanical Drawing List............................................................................................51
C-1 Mechanical Drawing List............................................................................................65
Thermal and Mechanical Design Guide 5
Revision History
Revision
Number
-001 • Initial release March 2009
Description Revision Date
§
6 Thermal and Mechanical Design Guide
Introduction
1 Introduction
This document provides guidelines for the design of thermal and mechanical solutions
for the:
• Intel® X eon® Processor 3500 Series
Unless specifically required for clarity , this document will use “processor” in place of the
specific product names. The components described in this document include:
• The processor thermal solution (heatsink) and associated retention hardware.
• The LGA1366 socket and the Independent Loading Mechanism (ILM) and back
plate.
Figure 1-1. Processor Thermal Solution & LGA1366 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
processor Datasheet.
Thermal/Mechanical Design Guide 7
1.1 References
Material and concepts available in the following documents may be beneficial when
reading this document.
Table 1-1. Reference Documents
Document Location Notes
Intel® Xeon® Processor 3500 Series Processor Datasheet,
Volume 1
Intel® Xeon® Processor 3500 Series Processor Datasheet,
Volume 2
Intel® Xeon® Processor 3500 Series Processor Specification
Update
Notes:
1. Available electronically
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 package used to enhance the
ILM Independent Loading Mechanism provides the force needed to seat the 1366-LGA land
IOH Input Output Hub: a component of the chipset that provides I/O connections to PCIe,
LGA1366 socket The processor mates with the system board through this surface mount, 1366-contact
PECI The Platform Environment Control Interface (PECI) is a one- wire in terface that pro vides
Ψ
CA
Ψ
CS
Ψ
SA
T
CASE
T
CASE_MAX
TCC Thermal Control Circuit: Thermal monitor uses the TCC to reduce the die temperature
T
CONTROL
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.
drives and other peripherals
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
The case temperature of the TTV measured at the geometric 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
Introduction
321332 1
321344 1
321333 1
– TLA) / Total
CASE
– TS) / Total
CASE
– TLA) / Total Package Power.
S
8 Thermal/Mechanical Design Guide
Introduction
Table 1-2. Terms and Descriptions (Sheet 2 of 2)
Term Description
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 case temperature specification of the TTV at a given power level.
TIM Thermal Interface Material: The thermally conductive compound between the heatsink
T
AMBIENT
T
SA
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.
§
Thermal/Mechanical Design Guide 9
Introduction
10 Thermal/Mechanical Design Guide
LGA1366 Socket
2 LGA1366 Socket
This chapter describes a surface mount, LGA (Land Grid Array) socket intended for
Intel® Xeon® Processor 3500 Series. The socket provides I/O, power and ground
contacts. The socket contains 1366 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 1366 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 integral to having
a uniform load on the socket solder joints. Socket loading specifications are listed in
Chapter 4.
Figure 2-1. LGA1366 Socket with Pick and Place Cover Removed
package socket
package
cavity
cavity
socket
Thermal/Mechanical Design Guide 11
Figure 2-2. LGA1366 Socket Contact Numbering (Top View of Socket)
AP
AN
AM
AL
AK
AJ
AH
AG
AF
AE
AD
AC
AB
AA
Y
W
V
U
T
R
P
N
M
L
K
J
H
G
F
E
D
C
B
A
31 29 27 25 23 21 19 17 15 13 11 9 7 5
32 30 28 26 24 22 20 18 16 14 12 10 8 6 4
AR
AU
AT
LGA1366 Socket
BA
AY
AW
AV
43 41 39 37 35 33 31 29 27 25 23 21 19 17 15 13
42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12
BA
AY
AW
AV
AU
AT
AR
AP
AN
AM
AL
AK
AJ
AH
AG
AF
AE
AD
AC
AB
AA
Y
W
V
U
T
R
P
N
M
L
K
J
H
G
F
E
D
C
B
A
12 Thermal/Mechanical Design Guide
LGA1366 Socket
2.1 Board Layout
The land pattern for the LGA1366 socket is 40 mils X 40 mils (X by Y), and the pad size
is 18 mils. 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.
Figure 2-3. LGA1366 Socket Land Pattern (Top View of Board)
A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA
B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY
32
32
31
31
30
30
29
29
28
28
27
27
26
26
25
25
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4
3
3
2
2
1
1
A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA
B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY
43
42
41
40
39
38
37
36
35
34
33
32
31
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25
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21
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12
Thermal/Mechanical Design Guide 13
2.2 Attachment to Motherboard
The socket is attached to the motherboard by 1366 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
LGA1366 Socket
ILM
LGA 1366 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 Chapter 7.
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 1366 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
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.
14 Thermal/Mechanical Design Guide
LGA1366 Socket
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 Chapter 7 without degrading.
As indicated in Figure 2-5, the cover remains on the socket during ILM installation, and
should remain on whenever possible to help prevent damage to the socket contacts.
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.
The covers are designed to be interchangeable between socket suppliers. As indicated
in Figure 2-5, a Pin1 indicator on the cover provides a visual reference for proper
orientation with the socket.
Figure 2-5. Pick and Place Cover
ILM
Installation
Pin 1 Pin 1
Pick and
Place Cover
Thermal/Mechanical Design Guide 15
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.
• 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.
LGA1366 Socket
orientation
orientation
notch
notch
alignment
Pin1 triangle
Pin1 triangle
access
access
orientation
orientation
post
post
Pin1 chamfer
Pin1 chamfer
alignment
walls
walls
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 4.2 for the calculated IHS height above the motherboard.
16 Thermal/Mechanical Design Guide
LGA1366 Socket
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:
• LGA1366: 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.
LGA1366 and the manufacturer's insignia are molded or laser marked on the side wall.
2.7 Component Insertion Forces
Any actuation must meet or exceed SEMI S8-95 Safety Guidelines for Ergonomics/
Human Factors Engineering of Semiconductor Manu facturing Equipment, example Table
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 keep-
out drawings provided in Appendix B to ensure compatibility with the reference thermal
mechanical components.
Thermal/Mechanical Design Guide 17
2.9 LGA1366 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 2-7
.
Figure 2-7. LGA1366 NCTF Solder Joints
identifies the NCTF solder joints.
A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA
B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY
32
32
31
31
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3
2
2
1
1
A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA
B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY
LGA1366 Socket
43
42
41
40
39
38
37
36
35
34
33
32
31
30
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12
18 Thermal/Mechanical Design Guide
§
Independent Loading Mechanism (ILM)
3 Independent Loading
Mechanism (ILM)
The Independent Loading Mechanism (ILM) provides the force needed to seat the
1366-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 integral to the overall functionality of the LGA1366
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 consists of two assemblies that will be procured as a set from the enabled
vendors. These two components are ILM cover assembly and back plate.
3.1.1 ILM Cover Assembly Design Overview
The ILM Cover 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 cover 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.
Thermal/Mechanical Design Guide 19
Figure 3-1. ILM Cover Assembly
Load Lever
Load Lever
Load Plate
Load Plate
Independent Loading Mechanism (IL M )
Captive Fastener (4x)
Captive Fastener (4x)
Frame
Frame
3.1.2 ILM Back Plate Design Overview
The back plate for single processor workstation products consists of a flat steel back
plate with threaded studs for ILM 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 insulator is pre-applied.
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 3-2), the back plate is placed in a fixture. Holes in the motherboard
provide alignment to the threaded studs. In step 2, the ILM cover assembly is placed
over the socket and threaded studs. Using a T20 Torx* driver fasten the ILM cover
assembly to the back plate with the four captive fasteners. Torque to 8 ± 2 inchpounds. The length of the threaded studs accommodate board thicknesses from
0.062” to 0.100”.
20 Thermal/Mechanical Design Guide
Independent Loading Mechanism (ILM)
.
Figure 3-2. ILM Assembly
Socket Body Reflowed on board
Socket Body Reflowed on board
Socket Body with Back Plate on board
Socket Body with Back Plate on board
Step 1 Step 2
Step 1 Step 2
Thermal/Mechanical Design Guide 21
As indicated in Figure 3-3, socket protrusion and ILM key features prevent 180-degree
rotation of ILM cover assembly with respect to the socket. The result is a specific Pin 1
orientation with respect to the ILM lever.
Figure 3-3. Pin1 and ILM Lever
Independent Loading Mechanism (IL M )
Protrusion
ILM Key
ILM
Lever
Pin 1
§
22 Thermal/Mechanical Design Guide
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