Intel 640 User Guide - Page 70

Heatsink Clip Load Metrology

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70

Thermal/Mechanical Design Guide

B.2.2

Typical Test Equipment

For the heatsink clip load measurement, use equivalent test equipment to that listed in Table 6.

Table 6. Typical Test Equipment

Item

Description

Part Number (Model)

Load cell

Notes: 1, 5

Honeywell-Sensotec* Model 13 subminiature load cells,

compression only

Select a load range depending on load level being tested.

www.sensotec.com

AL322BL

Data Logger (or

scanner)

Notes: 2, 3, 4

Vishay Measurements Group Model 6100 scanner with a

6010A strain card (one card required per channel).

Model 6100

NOTES:

1.

Select load range depending on expected load level. It is usually better, whenever possible, to

operate in the high end of the load cell capability. Check with your load cell vendor for further

information.

2.

Since the load cells are calibrated in terms of mV/V, a data logger or scanner is required to supply 5

volts DC excitation and read the mV response. An automated model will take the sensitivity

calibration of the load cells and convert the mV output into pounds.

3.

With the test equipment listed above, it is possible to automate data recording and control with a

6101-PCI card (GPIB) added to the scanner, allowing it to be connected to a PC running LabVIEW*

or Vishay's StrainSmart* software.

4.

IMPORTANT

: In addition to just a zeroing of the force reading at no applied load, it is important to

calibrate the load cells against known loads. Load cells tend to drift. Contact your load cell vendor for

calibration tools and procedure information.

5.

When measuring loads under thermal stress (bake for example), load cell thermal capability must be

checked, and the test setup must integrate any hardware used along with the load cell. For example,

the Model 13 load cells are temperature compensated up to 71 °C, as long as the compensation

package (spliced into the load cell's wiring) is also placed in the temperature chamber. The load cells

can handle up to 121 °C (operating), but their uncertainty increases according to 0.02% rdg/°F.

B.3

Test Procedure Examples

The following sections give two examples of load measurement. However, this is not meant to be

used in mechanical shock and vibration testing.

Any mechanical device used along with the heatsink attach mechanism will need to be included in

the test setup (i.e., back plate, attach to chassis, etc.).

Prior to any test, make sure that the load cell has been calibrated against known loads, following

load cell vendor’s instructions.

Section	Page
Contents	3
Figures	6
Tables	7
Revision History	8
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	12
2 Processor Thermal/Mechanical Information	15
2.1 Mechanical Requirements	15
2.1.1 Processor Package	15
2.1.2 Heatsink Attach	17
2.1.2.1 General Guidelines	17
2.1.2.2 Heatsink Clip Load Requirement	17
2.1.2.3 Additional Guidelines	18
2.2 Thermal Requirements	18
2.2.1 Processor Case Temperature	18
2.2.2 Thermal Profile	19
2.2.3 TCONTROL	20
2.3 Heatsink Design Considerations	21
2.3.1 Heatsink Size	22
2.3.2 Heatsink Mass	22
2.3.3 Package IHS Flatness	22
2.3.4 Thermal Interface Material	23
2.4 System Thermal Solution Considerations	23
2.4.1 Chassis Thermal Design Capabilities	23
2.4.2 Improving Chassis Thermal Performance	23
2.4.3 Summary	24
2.5 System Integration Considerations	24
3 Thermal Metrology	25
3.1 Characterizing Cooling Performance Requirements	25
3.1.1 Example	26
3.2 Processor Thermal Solution Performance Assessment	27
3.3 Local Ambient Temperature Measurement Guidelines	27
3.4 Processor Case Temperature Measurement Guidelines	30
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 Operation and Configuration	33
4.2.4 On-Demand Mode	34
4.2.5 System Considerations	34
4.2.6 Operating System and Application Software Considerations	35
4.2.7 On-Die Thermal Diode	35
4.2.7.1 Reading the On-Die Thermal Diode Interface	35
4.2.7.2 Correction Factors for the On-Die Thermal Diode	36
4.2.8 THERMTRIP# Signal	37
4.2.8.1 Cooling System Failure Warning	37
5 Intel® Thermal/Mechanical Reference Design Information	39
5.1 Intel Validation Criteria for the Reference Design	39
5.1.1 Heatsink Performance Target	39
5.1.2 Acoustics	40
5.1.3 Altitude	40
5.1.4 Reference Heatsink Thermal Validation	41
5.1.5 Fan Performance for Active Heatsink Thermal Solution	41
5.2 Environmental Reliability Testing	42
5.2.1 Structural Reliability Testing	42
5.2.1.1 Random Vibration Test Procedure	42
5.2.1.2 Shock Test Procedure	42
5.2.2 Power Cycling	44
5.2.3 Recommended BIOS/Processor/Memory Test Procedures	44
5.3 Material and Recycling Requirements	44
5.4 Safety Requirements	45
5.5 Geometric Envelope for ATX Intel® Reference Thermal Mechanical Design	45
5.6 ATX Reference Thermal Mechanical Solution for the Intel® Pentium® 4 Processor in the 775–Land LGA Package	46
5.7 Reference Attach Mechanism	48
5.7.1 Structural Design Strategy	48
5.7.2 Mechanical Interface to the Reference Attach Mechanism	49
6 Acoustic Fan Speed Control	53
6.1 Acoustic Fan Speed Control	53
6.2 Thermal Solution Design	53
6.2.1 Compliance to Thermal Profile	53
6.2.2 Determine Thermistor Set Points	53
6.2.3 Minimum Fan Speed Set Point	54
6.3 Board and System Implementation	55
6.3.1 Choosing Fan Speed Control Settings	55
6.3.1.1 Temperature to begin Fan Acceleration	56
6.3.1.2 Minimum PWM Duty Cycle	58
6.4 Combining Thermistor and Thermal Diode Control	59

Intel 640 User Guide - Page 70

Test Procedure Examples

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