R
4
Thermal/Mechanical Design Guide
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
5.2.1.2.1
Recommended Test Sequence
...........................
43
5.2.1.2.2
Post-Test Pass Criteria
.......................................
43
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
6.5
Interaction of Thermal Profile and T
CONTROL
.........................................................
59
Appendix A
LGA775 Socket Heatsink Loading
....................................................................................
61
A.1
LGA775 Socket Heatsink Considerations
............................................................
61
A.2
Metric for Heatsink Preload for ATX/μATX Designs Non-Compliant with Intel
Reference Design
.................................................................................................
61
A.2.1
Heatsink Preload Requirement Limitations
..........................................
61