Intel QX9770 Design Guidelines - Page 48

LGA775 Socket Heatsink Loading

48

Thermal and Mechanical Design Guidelines

5.2.3.1

Tubing Material Selection

Tubing material selection requires balancing several different criteria. The parameters

that were considered were cost, flexibility, flammability and vapor transmissibility.

Three different types of tubing materials were tested for liquid loss by connecting a

know length of tubing to the ALCT pump and measuring the assembly weight prior to

the start and periodically during the test to quantify the loss. The liquid evaporation

and migration of vapor through the plastic walls to atmosphere is the mode of liquid

loss that is affected by the internal structure of plastic and its wall thickness. The

pumps were run at 1450 RPM and T

LIQUID

was maintained at 50 ºC. An extremely

accurate scale is required to measure the weekly losses that allow for the calculation

of a loss rate.

The results for 3 different materials are summarized in Table 7. The Norprene

®

tubing

configuration had the lowest loss rate of 0.25 grams/week and was chosen as the

tubing material for ALCT. Material parameters are 3/8” internal diameter and 5/8”

outer diameter (1/8” wall thickness).

Table 7. The Weekly Loss Rate of Different Tubing Materials

Tubing Material

Loss Rate (grams/week)

Polyurethene

5.0

PVC

1.2

Norprene

®

0.25

5.2.3.2

Reservoir Sizing

The liquid loss through vapor migration through the tubing walls and joints can be

minimized but not eliminated as shown by the relatively impermeable material of

Norprene

®

rubber. The metal tubing was not a good option due to the flexibility

needed for the assembly of the solution inside of a chassis. The effect of liquid loss

can be mitigated at least for a reasonable operational life of the solution by providing

a liquid reservoir. A continuous operation test at 50 ºC and 1450 RPM was conducted

with assembly mass monitored every week to identify weekly mass loss rate. The

assembly mass loss data with 3 samples for 7 weeks duration is shown in Figure 13.

The data shows that average loss rate was 0.25-0.30 grams/week and is reasonably

consistent for 3 samples. The reservoir size of 38 milli-liters (38 grams for water) was

chosen to provide 152 weeks (approximately 3 years) of operational life. The pump is

expected to have additional resilience to liquid loss prior to significant impact to

thermal performance.

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 48

Tubing Material Selection, 5.2.3.2 Reservoir Sizing

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