Intel E2160 Design Guide - Page 44

Intel

®

Core

TM

2 Duo E6400, E4300, and Intel

®

Pentium

®

Dual-Core E2160 Processor—LGA775

Socket Heatsink Loading

Intel

®

Core

TM

2 Duo E6400, E4300, and Intel

®

Pentium

®

Dual-Core E2160 Processor

TDG

October 2007

44

Order Number: 315279 - 003US

Appendix A LGA775 Socket Heatsink Loading

A.1

LGA775 Socket Heatsink Considerations

Heatsink clip load is traditionally used for:

•

Mechanical performance in mechanical shock and vibration

•

Thermal interface performance

—

Required preload depends on TIM

—

Preload can be low for thermal grease

In addition to mechanical performance in mechanical shock and vibration and TIM

performance, the LGA775 socket requires a minimum heatsink preload to protect

against fatigue failure of socket solder joints.

Solder ball tensile stress is originally created when, after inserting a processor into the

socket, the LGA775 socket load plate is actuated. In addition, solder joint shear stress

is caused by coefficient of thermal expansion (CTE) mismatch induced shear loading.

The solder joint compressive axial force (Faxial) induced by the heatsink preload helps

to reduce the combined joint tensile and shear stress.

Overall, the heatsink required preload is the minimum preload needed to meet all of

the above requirements: Mechanical shock and vibration and TIM performance AND

LGA775 socket protection against fatigue failure.

A.2

Metric for Heatsink Preload for Designs Non-Compliant

with Intel Reference Design

A.2.1

Heatsink Preload Requirement Limitations

Heatsink preload by itself is not an appropriate metric for solder joint force across

various mechanical designs and does not take into account other factors such as:

•

Heatsink mounting hole span

•

Heatsink clip/fastener assembly stiffness and creep

•

Board stiffness and creep

•

Board stiffness is modified by fixtures like backing plate, chassis attach, etc.

Simulation shows that the solder joint force (F

axial

) is proportional to the board

deflection measured along the socket diagonal. The matching of Faxial required to

protect the LGA775 socket solder joint in temperature cycling is equivalent to matching

a target MB deflection.

Therefore, the heatsink preload for LGA775 socket solder joint protection against

fatigue failure can be more generally defined as the load required to create a target

board downward deflection throughout the life of the product.

Section	Page
Intel® CoreTM 2 Duo E6400, E4300, and Intel® Pentium® Dual-Core E2160 Processor: Thermal Design Guide	1
Contents	3
Figures	5
Tables	5
Revision History	6
1.0 Introduction	7
1.1 Document Goals and Scope	7
1.1.1 Importance of Thermal Management	7
1.1.2 Document Goals	7
1.1.3 Document Scope	7
1.2 References	9
1.3 Definition of Terms	9
2.0 Processor Thermal/Mechanical Information	11
2.1 Mechanical Requirements	11
2.1.1 Processor Package	11
2.1.2 Heatsink Attach	12
2.2 Thermal Requirements	14
2.2.1 Processor Case Temperature	14
2.2.2 Thermal Profile	15
2.2.3 Tcontrol	16
2.3 Heatsink Design Considerations	17
2.3.1 Heatsink Size	17
2.3.2 Heatsink Mass	18
2.3.3 Package IHS Flatness	18
2.3.4 Thermal Interface Material	18
2.4 System Thermal Solution Considerations	19
2.4.1 Chassis Thermal Design Capabilities	19
2.4.2 Improving Chassis Thermal Performance	19
2.4.3 Summary	19
2.5 System Integration Considerations	20
3.0 Thermal Metrology	21
3.1 Characterizing Cooling Performance Requirements	21
3.1.1 Example	22
3.2 Processor Thermal Solution Performance Assessment	23
3.3 Local Ambient Temperature Measurement Guidelines	23
3.4 Processor Case Temperature Measurement Guidelines	25
4.0 Thermal Management Logic and Thermal Monitor Feature	26
4.1 Processor Power Dissipation	26
4.2 Thermal Monitor Implementation	26
4.2.1 PROCHOT# Signal	27
4.2.2 Thermal Control Circuit	27
4.2.3 Thermal Monitor 2	28
4.2.4 Operation and Configuration	29
4.2.5 On-Demand Mode	30
4.2.6 System Considerations	30
4.2.7 Operating System and Application Software Considerations	31
4.2.8 THERMTRIP# Signal	31
4.2.9 Cooling System Failure Warning	31
4.2.10 Digital Thermal Sensor	31
4.2.11 Platform Environmental Control Interface (PECI)	32
5.0 Intel® Reference Thermal Solution	33
5.1 Thermal Solution Requirements	33
5.2 PICMG 1.3 Form Factor	34
5.3 ATX/BTX form factors	36
5.4 Altitude	36
5.5 Geometric Envelope for Intel Reference PICMG 1.3 Thermal Mechanical Design	37
6.0 Intel® Quiet System Technology (Intel® QST)	38
6.1 Intel® QST Algorithm	38
6.1.1 Output Weighting Matrix	39
6.1.2 Proportional-Integral-Derivative (PID)	39
6.2 Board and System Implementation of Intel® QST	41
6.3 Intel® QST Configuration and Tuning	43
6.4 Fan Hub Thermistor and Intel® QST	43
Appendix A LGA775 Socket Heatsink Loading	44
A.1 LGA775 Socket Heatsink Considerations	44
A.2 Metric for Heatsink Preload for Designs Non-Compliant with Intel Reference Design	44
A.2.1 Heatsink Preload Requirement Limitations	44
A.2.2 Motherboard Deflection Metric Definition	45
A.2.3 Board Deflection Limits	46
A.2.4 Board Deflection Metric Implementation Example	47
A.2.5 Additional Considerations	48
A.3 Heatsink Selection Guidelines	49
Appendix B Thermal Interface Management	50
B.1 Bond Line Management	50
B.2 Interface Material Area	50
B.3 Interface Material Performance	50
Appendix C Case Temperature Reference Metrology	51
C.1 Objective and Scope	51
Appendix D Mechanical Drawings	52

Intel E2160 Design Guide - Page 44

Appendix A LGA775 Socket Heatsink Loading, A.1 LGA775 Socket Heatsink Considerations

Page 44 highlights