Intel Celeron D Guide

Intel®Celeron®D Processor in
the 775-Land LGA Package for
Embedded Applications
Thermal Design Guide
July 2005
Order #303730-002

2Intel®Celeron®D Processor in the 775-Land LGA Package Thermal Design Guide
Order #303730
Contents
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Contents
Contents
1.0 Introduction....................................................................................................................................6
1.1 Document Goals and Scope.................................................................................................6
1.1.1 Importance of Thermal Management.......................................................................6
1.1.2 Document Goals......................................................................................................6
1.1.3 Document Scope .....................................................................................................6
1.2 References ...........................................................................................................................7
1.3 Terms and Definitions...........................................................................................................7
2.0 Processor Thermal/Mechanical Information...............................................................................9
2.1 Mechanical Requirements ....................................................................................................9
2.1.1 Processor Package..................................................................................................9
2.1.2 Heatsink Attach......................................................................................................10
2.1.2.1 General Guidelines ................................................................................10
2.1.2.2 Heatsink Clip Load Requirement ...........................................................11
2.1.2.3 Additional Guidelines .............................................................................11
2.2 Thermal Requirements .......................................................................................................11
2.2.1 Processor Case Temperature and Power Dissipation...........................................12
2.2.2 Thermal Profile ......................................................................................................12
2.2.3 TCONTROL...............................................................................................................13
2.3 Heatsink Design Considerations.........................................................................................14
2.3.1 Heatsink Size.........................................................................................................15
2.3.2 Heatsink Mass .......................................................................................................15
2.3.3 Package IHS Flatness ...........................................................................................15
2.3.4 Thermal Interface Material.....................................................................................16
2.3.5 Summary ...............................................................................................................16
2.4 System Thermal Solution Considerations...........................................................................16
2.4.1 Improving Chassis Thermal Performance..............................................................16
3.0 Thermal Metrology ......................................................................................................................18
3.1 Characterizing Cooling Performance Requirements ..........................................................18
3.1.1 Example.................................................................................................................19
3.2 Processor Thermal Solution Performance Assessment .....................................................20
3.3 Local Ambient Temperature Measurement Guidelines ......................................................20
3.3.1 Measuring Active Heatsinks ..................................................................................20
3.3.2 Measuring Passive Heatsinks................................................................................21
3.4 Processor Case Temperature Measurement Guidelines....................................................22
4.0 Thermal Management Logic and Thermal Monitor ..................................................................23
4.1 Processor Power Dissipation..............................................................................................23
4.2 Thermal Monitor Implementation........................................................................................23
4.2.1 PROCHOT# Signal................................................................................................23
4.2.2 Thermal Control Circuit..........................................................................................24
4.2.3 Operation and Configuration..................................................................................25
4.2.4 On-Demand Mode .................................................................................................25
4.2.5 System Considerations..........................................................................................26
4.2.6 Operating System and Application Software Considerations ................................26
4.2.7 On-Die Thermal Diode...........................................................................................26

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4.2.7.1 Reading the On-Die Thermal Diode Interface........................................27
4.2.7.2 Correction Factors for the On-Die Thermal Diode.................................27
4.2.8 THERMTRIP# Signal.............................................................................................28
4.2.8.1 Cooling System Failure Warning ...........................................................28
4.2.9 How On-Die Thermal Diode, TCONTROL and Thermal Profile Work Together....29
4.2.9.1 On-Die Thermal Diode Less than TCONTROL......................................29
4.2.9.2 On-Die Thermal Diode Greater than TCONTROL.................................29
4.3 Acoustic Fan Speed Control...............................................................................................29
5.0 Intel Enabled Thermal Solutions................................................................................................30
5.1 Thermal Solution Requirements.........................................................................................30
5.2 ATX Form Factor................................................................................................................31
5.3 1U Form Factor...................................................................................................................31
5.4 2U Form Factor...................................................................................................................33
5.5 Reference Thermal Mechanical Solution............................................................................35
6.0 Conclusion...................................................................................................................................36
A LGA775 Socket Heatsink Loading.............................................................................................37
B Heatsink Clip Load Metrology....................................................................................................42
C Thermal Interface Management..................................................................................................46
D Case Temperature Reference Methodology .............................................................................47
E Board Level PWM and Fan Speed Control Requirements.......................................................57
F Mechanical Drawings..................................................................................................................58
G Vendor Information .....................................................................................................................64
Figures
1 Package IHS Load Areas .............................................................................................................9
2 Processor Case Temperature Measurement Location...............................................................12
3 Example Thermal Profile............................................................................................................13
4 Processor Thermal Characterization Parameter Relationships..................................................19
5 Measuring TLA— Active Heatsink...............................................................................................21
6 Measuring TLA— Passive Heatsink............................................................................................22
7 Concept for Clocks under Thermal Monitor Control ...................................................................24
8 Thermal Characterization Parameters for Various Operating Conditions ..................................31
9 1U Copper Heatsink ...................................................................................................................32
10 1U Thermal Solution Z-Height Constraints.................................................................................33
11 2U Copper Heatsink ...................................................................................................................33
12 Case-to-Ambient Thermal Characterization Parameter ΨCA (°C/W)..........................................34
13 2U Height Restrictions................................................................................................................35
14 Board Deflection Definition.........................................................................................................38
15 Example: Defining Heatsink Preload Meeting Board Deflection Limit........................................40
16 Load Cell Installation in Machined Heatsink Base Pocket – Bottom View .................................43
17 Load Cell Installation in Machined Heatsink Base Pocket – Side View......................................43
18 Preload Test Configuration.........................................................................................................44

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19 FC-LGA4 Package Reference Groove Drawing.........................................................................49
20 IHS Reference Groove on the FC-LGA4 Package.....................................................................50
21 IHS Groove Orientation Relative to the LGA775 Socket ............................................................50
22 Bending the Tip of the Thermocouple.........................................................................................51
23 Securing Thermocouple Wires with Kapton* Tape Prior to Attach.............................................51
24 Thermocouple Bead Placement (View 1)...................................................................................52
25 Thermocouple Bead Placement (View 2)...................................................................................52
26 Position Bead on Groove Step ...................................................................................................53
27 Detailed Thermocouple Bead Placement...................................................................................53
28 Using 3D Micromanipulator to Secure Bead Location................................................................54
29 Measuring Resistance between Thermocouple and IHS............................................................54
30 Applying the Adhesive on the Thermocouple Bead....................................................................55
31 Thermocouple Wire Management in the Groove........................................................................55
32 Removing Excess Adhesive from IHS........................................................................................56
33 Filling the Groove with Adhesive ................................................................................................56
34 ATX/µATX Motherboard Keep-Out Footprint Definition and Height Restrictions
for Enabling Components, Sheet 1.............................................................................................59
35 ATX/µATX Motherboard Keep-Out Footprint Definition and Height Restrictions
for Enabling Components, Sheet 2.............................................................................................60
36 ATX/µATX Motherboard Keep-Out Footprint Definition and Height Restrictions
for Enabling Components, Sheet 3.............................................................................................61
37 1U/2U Motherboard Component Keep-In Definition, Primary Side ............................................62
38 1U/2U Motherboard Component Keep-In Definition, Secondary Side........................................63
Tables
1 Reference Documents..................................................................................................................7
2 Terms and Definitions...................................................................................................................7
3 Thermal Diode Interface.............................................................................................................27
4 Thermal Characterization Parameter at Various TLA Levels .....................................................30
5 Enabled Thermal Solutions.........................................................................................................31
6 Board Deflection Configuration Definitions.................................................................................38
7 Typical Test Equipment..............................................................................................................44
8 Definitions...................................................................................................................................47
9 Supporting Test Equipment........................................................................................................47
10 Mechanical Drawings..................................................................................................................58
11 Intel Reference Component Thermal Solution Provider.............................................................64
Revision History
Date Revision Description
July 2005 002 Updated Table 1 and Table 4.
September 2004 001 Changes to branding. First public release.

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Introduction
1.0 Introduction
1.1 Document Goals and Scope
1.1.1 Importance of Thermal Management
The objective of thermal management is to ensure that the temperatures of all components in a
system are maintained within their functional temperature range. Within this temperature range, a
component is expected to meet its specified performance. Operation outside the functional
temperature range can degrade system performance, cause logic errors or cause component and/or
system damage. Temperatures exceeding the maximum operating limit of a component may result
in irreversible changes in the operating characteristics of this component.
In a system environment, the processor temperature is a function of both system and component
thermal characteristics. The system level thermal constraints consist of the local ambient air
temperature and airflow over the processor as well as the physical constraints at and above the
processor. The processor temperature depends in particular on the component power dissipation,
the processor package thermal characteristics, and the processor thermal solution.
All of these parameters are affected by the continued push of technology to increase processor
performance levels (higher operating speeds, GHz) and packaging density (more transistors). As
operating frequencies increase and packaging size decreases, the power density increases while the
thermal solution space and airflow typically become more constrained or remains the same within
the system. The result is an increased importance on system design to ensure that thermal design
requirements are met for each component, including the processor, in the system.
1.1.2 Document Goals
Depending on the type of system and chassis characteristics, new system and component designs
may be required to provide adequate cooling for the processor. The goal of this Thermal Design
Guide is to provide an understanding of these thermal characteristics and discuss guidelines for
meeting the thermal requirements imposed on single processor systems for the Intel®Celeron®D
Processor in the 775-Land LGA Package for Embedded Applications. The specifications for this
processor (also referred to herein as the Intel Celeron D Processor in the 775-Land LGA Package)
are delineated in the Intel®Celeron®D Processor in the 775-Land LGA Package Datasheet.
1.1.3 Document Scope
This document discusses the thermal management techniques for the Intel Celeron D Processor in
the 775-Land Package.
The processor physical dimensions and thermal specifications used in this document are for
illustration only. Refer to the Intel Celeron D Processor in the 775-Land Package Datasheet for
product dimensions, thermal power dissipation and maximum case temperature. In case of conflict,
the datasheet supersedes this document.

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Introduction
1.2 References
Material and concepts available in the following documents may be beneficial when reading this
document.
1.3 Terms and Definitions
Table 1. Reference Documents
Document Comment
Fan Specification for 4 Wire PWM Controlled Fans http://www.formfactors.org/dev eloper%5Cspecs%5CREV1_2_
Public.pdf
Intel®Celeron®D Processors 3xx Sequence Datasheet on 90nm Process
in 775-Land Package Intel document #304092
Intel® Pentium® 4 Processor 570/571, 560/561, 550/551, 540/541, 530/531
and 520/521 Supporting Hyper-Threading Technology Datasheet Intel document # 302351
Intel®Pentium®4 Processor on 90 nm Process in the 775-Land LGA
Package Thermal Design Guide Intel document #302553
LGA775 Socket Mechanical Design Guide Intel document #302666
Performance ATX Desktop System Thermal Design Suggestions http://www.formfactors.org/
Performance microATX Desktop System Thermal Design Suggestions http://www.formfactors.org/
Server System Infrastructure Thin Electronics Bay Specifications http://www.ssiforum.org/
Table 2. Terms and Definitions (Sheet 1 of 2)
Term Description
TAThe measured ambient temperature locally surrounding the processor. The ambient
temperature should be measured just upstream of a passive heatsink or at the fan inlet
for an active heatsink. Also referred to as TLA
TCThe case temperature of the processor, measured at the geometric center of the topside
of the IHS.
TEThe ambient air temperature external to a system chassis. This temperature is usually
measured at the chassis air inlets.
TSHeatsink temperature measured on the underside of the heatsink base, at a location
corresponding to TC.
TC-MAX The maximum case temperature as specified in a component specification.
ΨCA
Case-to-ambient thermal characterization parameter (psi). A measure of thermal
solution performance using total package power. Defined as (TC– TA) / Total Package
Power.
NOTE: Heat source must be specified for Ψmeasurements.
ΨCS
Case-to-sink thermal characterization parameter. A measure of thermal interface
material performance using total package power. Defined as (TC– TS) / Total Package
Power.
NOTE: Heat source must be specified for Ψmeasurements.
ΨSA Sink-to-ambient thermal characterization parameter. A measure of heatsink thermal
performance using total package power. Defined as (TS– TA) / Total Package Power.
NOTE: Heat source must be specified for Ψmeasurements.

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Introduction
TIM Thermal Interface Material: The thermally conductive compound between the heatsink and the processor case. This material fills the air gaps and voids, and enhances the
transfer of the heat from the processor case to the heatsink.
PMAX The maximum power dissipated by a semiconductor component.
TDP Thermal Design Power: a power dissipation target based on worst-case applications.
Thermal solutions should be designed to dissipate the thermal design power.
IHS Integrated Heat Spreader: a thermally conductive lid integrated into a processor
package to improve heat transfer to a thermal solution through heat spreading.
LGA775 Socket The surface mount socket designed to accept the Intel Celeron D Processor in the
775-Land LGA Package.
ACPI Advanced Configuration and Power Interface.
Bypass Bypass is the area between a passive heatsink and any object that can act to form a duct. For this example, it can be expressed as a dimension away from the outside
dimension of the fins to the nearest surface.
FMB Flexible Motherboard Guideline: an estimate of the maximum value of a processor
specification over certain time periods. System designers should meet the FMB values
to ensure their systems are compatible with future processor releases. FMB1 and FMB2
are sequential estimates of processor specifications over time.
Thermal Monitor A feature on the Intel Celeron D Processor in the 775-Land LGA Package that attempts
to keep the processor’s die temperature within factory specifications.
TCC Thermal Control Circuit: Thermal Monitor uses the TCC to reduce die temperature by lowering effective processor frequency when the die temperature is very near its
operating limits.
TDIODE Temperature reported from the on-die thermal diode.
FSC Fan Speed Control: Thermal solution that includes a variable fan speed which is driven by a PWM signal and uses the on-die thermal diode as a reference to change the duty
cycle of the PWM signal.
TCONTROL_BASE Constant from the processor EMTS that is added to the TCONTROL_OFFSET that results
in the value for TCONTROL
TCONTROL_OFFSET Value read by the BIOS from a processor MSR and added to the TCONTROL_BASE that
results in the value for TCONTROL
TCONTROL TCONTROL is the specification limit for use with the on-die thermal diode.
PWM Pulse width modulation is a method of controlling a variable speed fan. The enabled 4 wire fans use the PWM duty cycle % from the fan speed controller to modulate the fan
speed.
Health Monitor
Component Any standalone or integrated component that is capable of reading the processor temperature and providing the PWM signal to the 4 pin fan header.
UA unit of measure used to define server rack spacing height. 1U is equal to 1.75 inches,
2U equals 3.50 inches, etc.
Table 2. Terms and Definitions (Sheet 2 of 2)

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Processor Thermal/Mechanical Information
2.0 Processor Thermal/Mechanical
Information
2.1 Mechanical Requirements
2.1.1 Processor Package
The Celeron D Processor in the 775-Land LGA Package is packaged in a Flip-Chip Land Grid
Array (FC-LGA4) package that interfaces with the motherboard via a LGA775 socket. Please refer
to the processor datasheet for detailed mechanical specifications.
The processor connects to the motherboard through a land grid array (LGA) surface mount socket.
The socket contains 775 contacts arrayed about a cavity in the center of the socket with solder balls
for surface mounting to the motherboard. The socket is named LGA775 socket. A description of
the socket can be found in the LGA775 Socket Mechanical Design Guide.
The package includes an integrated heat spreader (IHS) that is shown in Figure 1 for illustration
only. Refer to the processor datasheet for further information. In case of conflict, the package
dimensions in the processor datasheet supercede dimensions provided in this document.
The primary function of the IHS is to transfer the non-uniform heat distribution from the die to the
top of the IHS, out of which the heat flux is more uniform and spread over a larger surface area (not
the entire IHS area). This allows more efficient heat transfer out of the package to an attached
cooling device. The top surface of the IHS is designed to be the interface for contacting a heatsink.
Figure 1. Package IHS Load Areas
Top Surface of IHS
to install a heatsink
IHS Step
to interface with LGA775
Socket Load Plate
Substrate Top Surface of IHS
to install a heatsink
IHS Step
to interface with LGA775
Socket Load Plate
Substrate

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Processor Thermal/Mechanical Information
The IHS also features a step that interfaces with the LGA775 socket load plate, as described in
LGA775 Socket Mechanical Design Guide. The load from the load plate is distributed across two
sides of the package onto a step on each side of the IHS. It is then distributed by the package across
all of the contacts. When correctly actuated, the top surface of the IHS is above the load plate
allowing proper installation of a heatsink on the top surface of the IHS. The post-actuated seating
plane of the package is flush with the seating plane of the socket. Package movement during socket
actuation is along the Z direction (perpendicular to substrate) only. Refer to the LGA775 Socket
Mechanical Design Guide for further information about the LGA775 socket.
The processor datasheet gives details on the IHS geometry and tolerances, and IHS material.
The processor package has mechanical load limits that are specified in the processor datasheet. The
specified maximum static and dynamic load limits should not be exceeded during their respective
stress conditions. These include heatsink installation, removal, mechanical stress testing, and
standard shipping conditions.
•When a compressive static load is necessary to ensure thermal performance of the thermal
interface material (TIM) between the heatsink base and the IHS, it should not exceed the
corresponding specification given in the processor datasheet.
•When a compressive static load is necessary to ensure mechanical performance, it should not
exceed the corresponding specification given in the processor datasheet.
•The heatsink mass can also add additional dynamic compressive load to the package during a
mechanical shock event. Amplification factors due to the impact force during shock must be
taken into account in dynamic load calculations. The total combination of dynamic and static
compressive load should not exceed the processor datasheet compressive dynamic load
specification during a vertical shock. For example, with a 0.454 kg [1 lbm] heatsink, an
acceleration of 50G during an 11 ms trapezoidal shock with an amplification factor of 2 results
in approximately a 445 N [100 lbf] dynamic load on the processor package. If a 178 N [40 lbf]
static load is also applied on the heatsink for thermal performance of the TIM the processor
package could see up to a 623 N [140 lbf]. The calculation for the thermal solution of interest
should be compared to the processor datasheet specification.
No portion of the substrate should be used as a load-bearing surface.
Finally, the processor datasheet provides package handling guidelines in terms of maximum
recommended shear, tensile and torque loads for the processor IHS relative to a fixed substrate.
These recommendations should be followed in particular for heatsink removal operations.
2.1.2 Heatsink Attach
2.1.2.1 General Guidelines
There are no features on the LGA775 socket to directly attach a heatsink: a mechanism must be
designed to support the heatsink. In addition to holding the heatsink in place on top of the IHS, this
mechanism plays a significant role in the robustness of the system in which it is implemented, in
particular:
•Ensuring thermal performance of the TIM applied between the IHS and the heatsink. TIMs
based on phase change materials are very sensitive to applied pressure: the higher the pressure,
the better the initial performance. TIMs such as thermal greases are not as sensitive to applied
pressure. Designs should consider a possible decrease in applied pressure over time due to
potential structural relaxation in retention components.