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Intel 640 User Guide - Page 88

FSC Definitions Example

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Board Level PWM and Fan Speed Control Requirements R Figure 42. FSC Definitions Example Requirements Classification • Required - an essential part of the design necessary to meet specifications. Should be considered a pass or fail criterion in selection of a board. • Suggested - highly desired for consistency among designs. May be specified or expanded by the system integrator. The motherboard needs to have a fan speed control component that has the following characteristics: • PWM output programmable to 21-28 kHz (required). PWM output set to 25 kHz (Suggested) as this value is the design target for the reference and for the Boxed Pentium 4 Processor. • External/remote thermal diode measurement capability (required). • External/remote thermal diode sampling rate ≥ 4 times per second (required). • External/remote diode measurement is calibrated by the component vendor to account for the diode ideality and package series resistance as listed in the appropriate datasheet. (Suggested). Note: If the fan speed controller is not calibrated with the diode ideality and package series resistance, verify the board manufacturer has made provisions within the BIOS setup or other utility to input the corrections factors. Note: The BIOS, at a minimum, must program the settings in Table 8 or Table 9 into the fan speed controller. The values are the minimum required to establish a fan speed control algorithm consistent with this document, the reference thermal solution and Boxed Processor thermal solution. 88 Thermal/Mechanical Design Guide

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

Match case Limit results 1 per page

Board Level PWM and Fan Speed Control Requirements

Thermal/Mechanical Design Guide

Figure 42. FSC Definitions Example

Requirements Classification

•

Required – an essential part of the design necessary to meet specifications. Should be

considered a pass or fail criterion in selection of a board.

•

Suggested – highly desired for consistency among designs. May be specified or expanded by

the system integrator.

The motherboard needs to have a fan speed control component that has the following

characteristics:

•

PWM output programmable to 21–28 kHz (required). PWM output set to 25 kHz (Suggested)

as this value is the design target for the reference and for the Boxed Pentium 4 Processor.

•

External/remote thermal diode measurement capability (required).

•

External/remote thermal diode sampling rate

≥

4 times per second (required).

•

External/remote diode measurement is calibrated by the component vendor to account for the

diode ideality and package series resistance as listed in the appropriate datasheet.

(Suggested).

Note:

If the fan speed controller is not calibrated with the diode ideality and package series resistance,

verify the board manufacturer has made provisions within the BIOS setup or other utility to input

the corrections factors.

Note:

The BIOS, at a minimum, must program the settings in Table 8 or Table 9 into the fan speed

controller. The values are the minimum required to establish a fan speed control algorithm

consistent with this document, the reference thermal solution and Boxed Processor thermal

solution.