Intel QX9770 Design Guidelines - Page 47

Intel Thermal/Mechanical Reference Design Information

Thermal and Mechanical Design Guidelines

47

A list of failure mechanisms that were considered in design reliability testing are:

1.

Pump assembly cracking causing liquid loss

2.

Vapor loss through plastic walls and joints causing liquid loss

3.

Thermal performance degradation due to internal mechanisms affecting

CPU T

C

temperature

4.

Pump motor and printed circuit board performance degradation affecting

the pump RPM

All of the above mechanisms are expected to be active during the pump operation and

relatively inactive during the off mode and so all reliability testing needs to be

performed with pump on. The fatigue mechanisms (# 1) are additionally excited by

the cycling of temperature caused by on-off cycles. The real use condition is a

combination of continuous operation and on-off cycling and for the purpose of testing

can be separated into a) continuous operation and b) on-off power cycles. The liquid

temperature during continuous operation can be estimated by the heat exchanger

thermal resistance, TDP, and T

A

(e.g., at T

A

= 38 ºC, TDP = 130 W, and

Ψ

HX

= 0.05 ºC /W gives T

LIQUID

= 45 ºC). The calculated T

LIQUID

when fan is at its low

speed and T

A

= 26 ºC is expected to be approximately the same. A typical on-off cycle

can be assumed to be from ambient condition to T

LIQUID

= 45 ºC. The pump speed is

also controlled similar to a fan for acoustics and expected mean pump RPM was

estimated to be 1450 (range = 600-1700). The pump speed of 1450 was used to

simulate typical condition during with use condition.

Note:

The heat exchanger thermal resistance,

Ψ

HX

= (T

LIQUID

– T

A

)/(CPU power). T

A

is the air

approaching the heat exchanger.

The complete test matrix is summarized in the Table 6. The continuous operation tests

were slightly accelerated to reduce duration for failure. The cracking mechanism #1

was accelerated significantly by running at 75 ºC. The T

LIQUID

value was achieved by

applying a film heater to the bottom of the pump assembly alone (tubing and heat

exchanger were not included by a closed loop tube was used to provide impedance

from pump outlet to inlet).

Table 6. The Reliability Test Matrix

Use Condition

Test Conditions

Pump Speed

Included Failure

Mechanisms

Continuous operation

T

LIQUID

= 50 ºC

1450

2

T

LIQUID

= 50 ºC

1450

3, 4

T

LIQUID

= 75 ºC for 16

weeks

1450

1

On-off cycles

T

LIQUID

= 35-60 ºC,

7500 cycles

1450

1,2,3,4

Section	Page
1 Introduction	9
1.1 Document Goals and Scope	9
1.1.1 Importance of Thermal Management	9
1.1.2 Document Goals	9
1.1.3 Document Scope	10
1.2 References	11
1.3 Definition of Terms	11
2 Processor Thermal/Mechanical Information	13
2.1 Mechanical Requirements	13
2.1.1 Processor Package	13
2.1.2 Heatsink Attach	15
2.1.2.1 General Guidelines	15
2.1.2.2 The Pump Assembly Clip Load Requirement	15
2.1.2.3 Additional Guidelines	16
2.2 Thermal Requirements	16
2.2.1 Processor Case Temperature	16
2.2.2 Thermal Profile	17
2.2.3 TCONTROL	18
2.3 Heatsink Design Considerations	19
2.3.1 Heatsink Size	20
2.3.2 Package IHS Flatness	20
2.3.3 Thermal Interface Material	21
2.4 System Thermal Solution Considerations	21
2.4.1 Chassis Thermal Design Capabilities	21
2.4.2 Improving Chassis Thermal Performance	21
2.4.3 Summary	22
2.5 System Integration Considerations	22
3 Thermal Metrology	23
3.1 Characterizing Cooling Performance Requirements	23
3.1.1 Example	25
3.2 Processor Thermal Solution Performance Assessment	26
3.3 Local Ambient Temperature Measurement Guidelines	26
3.4 Processor Case Temperature Measurement Guidelines	29
4 Thermal Management Logic and Thermal Monitor Feature	31
4.1 Processor Power Dissipation	31
4.2 Thermal Monitor Implementation	31
4.2.1 PROCHOT# Signal	32
4.2.2 Thermal Control Circuit	32
4.2.3 Thermal Monitor 2	33
4.2.4 Operation and Configuration	34
4.2.5 On-Demand Mode	35
4.2.6 System Considerations	35
4.2.7 Operating System and Application Software Considerations	36
4.2.8 THERMTRIP# Signal	36
4.2.9 Cooling System Failure Warning	36
4.2.10 Digital Thermal Sensor	37
4.2.11 Platform Environmental Control Interface (PECI)	38
5 Intel Thermal/Mechanical Reference Design Information	39
5.1 Validation Results for the ATX Reference Design	39
5.1.1 Heatsink Performance	40
5.1.2 Acoustics	40
5.1.3 Altitude	41
5.1.4 Reference Heatsink Thermal Validation	41
5.1.5 Fan Motor Performance	42
5.1.6 Pump Motor Performance	43
5.2 Environmental Reliability Testing	44
5.2.1 Structural Reliability Testing	44
5.2.1.1 Random Vibration Test Procedure	44
5.2.1.2 Shock Test Procedure	45
5.2.2 Power Cycling	46
5.2.3 Reliability Testing	46
5.2.3.1 Tubing Material Selection	48
5.2.3.2 Reservoir Sizing	48
5.2.3.3 Reliability Test Results	50
5.2.4 Recommended BIOS/CPU/Memory Test Procedures	51
5.3 Material and Recycling Requirements	52
5.4 Safety Requirements	52
5.5 Geometric Envelope for Intel Reference ATX Thermal Mechanical Design	52
5.6 Reference Attach Mechanism	54
5.7 Socket and Voltage Regulation Cooling Strategy	55
6 Intel® Quiet System Technology (Intel® QST)	57
6.1 Intel® Quiet System Technology Algorithm	57
6.1.1 Output Weighting Matrix	58
6.1.2 Proportional-Integral-Derivative (PID)	58
6.2 Board and System Implementation of Intel® Quiet System Technology	60
6.3 Intel® QST Configuration & Tuning	62

Intel QX9770 Design Guidelines - Page 47

Table 6. The Reliability Test Matrix, CPU power. T

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