Intel® Celeron® D Processor in the 775-Land LGA Package for Embedded Applications Thermal Design Guide July 2005 Order #303730-002
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Contents Contents 1.0 Introduction.................................................................................................................................... 6 1.1 1.2 1.3 2.0 Processor Thermal/Mechanical Information ............................................................................... 9 2.1 2.2 2.3 2.4 3.0 Mechanical Requirements .................................................................................................... 9 2.1.1 Processor Package..........................
Contents 4.3 5.0 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.
Contents 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 FC-LGA4 Package Reference Groove Drawing ......................................................................... 49 IHS Reference Groove on the FC-LGA4 Package ..................................................................... 50 IHS Groove Orientation Relative to the LGA775 Socket ............................................................ 50 Bending the Tip of the Thermocouple......................................................
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.
Introduction 1.2 References Material and concepts available in the following documents may be beneficial when reading this document. Table 1. Reference Documents Document 1.3 Table 2. Comment Fan Specification for 4 Wire PWM Controlled Fans http://www.formfactors.org/dev eloper%5Cspecs%5CREV1_2_ Public.
Introduction Table 2. 8 Terms and Definitions (Sheet 2 of 2) 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.
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.
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.
Processor Thermal/Mechanical Information • Ensuring system electrical, thermal, and structural integrity under shock and vibration events. The mechanical requirements of the heatsink attach mechanism depend on the weight of the heatsink and the level of shock and vibration that the system must support. The overall structural design of the motherboard and the system have to be considered when designing the heatsink attach mechanism.
Processor Thermal/Mechanical Information Intel has introduced a new method for specifying the thermal limits for the Celeron D Processor in the 775-Land LGA Package. The new parameters are the Thermal Profile and TCONTROL. The Thermal Profile defines the maximum case temperature as a function of power being dissipated. TCONTROL is a specification used in conjunction with the temperature reported by the on-die thermal diode.
Processor Thermal/Mechanical Information To determine compliance to the thermal profile, a measurement of the actual processor power dissipated is required. The measured power is plotted on the Thermal Profile to determine the maximum case temperature. Using the example in Figure 3, a power dissipation of 70 W has a case temperature of 61 °C. Contact your Intel sales representative for assistance in processor power measurement.
Processor Thermal/Mechanical Information This is achieved in part by using the ΨCA vs. RPM and RPM vs. Acoustics (dBA) performance curves from the Intel enabled thermal solution. A thermal solution designed to meet the thermal profile should perform virtually the same for any value of TCONTROL. See Section 4.3, “Acoustic Fan Speed Control” on page 29, for details on implementing a design using Tcontrol and the Thermal Profile.
Processor Thermal/Mechanical Information 2.3.1 Heatsink Size The size of the heatsink is dictated by height restrictions for installation in a system and by the space available on the motherboard and other considerations for component height and placement in the area potentially impacted by the processor heatsink. The height of the heatsink must comply with the requirements and recommendations published for the motherboard form factor of interest.
Processor Thermal/Mechanical Information Intel recommends testing and validating heatsink performance in full mechanical enabling configuration to capture any impact of IHS flatness change due to combined socket and heatsink loading. While socket loading alone may increase the IHS warpage, the heatsink preload redistributes the load on the package and improves the resulting IHS flatness in the enabled state. 2.3.
Processor Thermal/Mechanical Information the amount of system airflow can be traded off against each other to meet specific system design constraints. Additional constraints are board layout, spacing, component placement, acoustic requirements and structural considerations that limit the thermal solution size. For more information, refer to the Performance ATX Desktop System Thermal Design Suggestions or Performance microATX Desktop System Thermal Design Suggestions documents available on the http://www.
Thermal Metrology 3.0 Thermal Metrology This chapter discusses guidelines for testing thermal solutions, including measuring processor temperatures. In all cases, the thermal engineer must measure power dissipation and temperature to validate a thermal solution. To define the performance of a thermal solution the thermal characterization parameter, Ψ (psi), will be used. 3.
Thermal Metrology ΨSA is a measure of the thermal characterization parameter from the bottom of the heatsink to the local ambient air. ΨSA is dependent on the heatsink material, thermal conductivity, and geometry. It is also strongly dependent on the air velocity through the fins of the heatsink. Figure 4 illustrates the combination of the different thermal characterization parameters. Figure 4.
Thermal Metrology 3.2 Processor Thermal Solution Performance Assessment Thermal performance of a heatsink should be assessed using a thermal test vehicle (TTV) provided by Intel. The TTV is a well-characterized thermal tool, whereas real processors can introduce additional factors that can impact test results. In particular, the power level from actual processors varies significantly, even when running the maximum power application provided by Intel, due to variances in the manufacturing process.
Thermal Metrology • If a variable speed fan is used, it may be useful to add a thermocouple taped to the barrier above the location of the temperature sensor used by the fan to check its speed setting against air temperature. When measuring TA in a chassis with a live motherboard, add-in cards, and other system components, it is likely that the TA measurements will reveal a highly non-uniform temperature distribution across the inlet fan section.
Thermal Metrology Figure 6. Measuring TLA— Passive Heatsink NOTE: Dimensions in drawing not to scale. 3.4 Processor Case Temperature Measurement Guidelines To ensure functionality and reliability, the Celeron D Processor in the 775-land LGA package is specified for proper operation when TC is maintained at or below the thermal profile as listed in the processor datasheet. The measurement location for TC is the geometric center of the IHS. Figure 2 shows the location for TC measurement.
Thermal Management Logic and Thermal Monitor 4.0 Thermal Management Logic and Thermal Monitor 4.1 Processor Power Dissipation An increase in processor operating frequency not only increases system performance, but also increases the processor power dissipation. The relationship between frequency and power is generalized in the following equation: P = CV2F Where P = power, C = capacitance, V = voltage, F = frequency.
Thermal Management Logic and Thermal Monitor when the processor has reached its maximum operating temperature or be driven from an external source to activate the TCC. The ability to activate the TCC via PROCHOT# can provide a means for thermal protection of system components. One application is the thermal protection of voltage regulators (VR). System designers can create a circuit to monitor the VR temperature and activate the TCC when the temperature limit of the VR is reached.
Thermal Management Logic and Thermal Monitor 4.2.3 Operation and Configuration To maintain compatibility with previous generations of processors, which have no integrated thermal logic, the Thermal Control Circuit portion of Thermal Monitor is disabled by default. During the boot process, the BIOS must enable the Thermal Control Circuit. Note: Thermal Monitor must be enabled to ensure proper processor operation. The Thermal Control Circuit feature can be configured and monitored in a number of ways.
Thermal Management Logic and Thermal Monitor 4.2.5 System Considerations Intel requires the Thermal Monitor and Thermal Control Circuit to be enabled for all Celeron D processors in the 775-land LGA package based systems. The thermal control circuit is intended to protect against short term thermal excursions that exceed the capability of a well designed processor thermal solution.
Thermal Management Logic and Thermal Monitor System integrators should note that there is no defined correlation between the on-die thermal diode and the processor case temperature. The temperature distribution across the die is affected by the power being dissipated, type of activity the processor is performing e.g., integer or floating point intensive and the leakage current.
Thermal Management Logic and Thermal Monitor TERROR = TMEASURED * (1 - NACTUAL / NTRIM) Where TERROR = correction factor to add to the reported temperature, TMEASURED = temperature reported by the thermal sensor (Kelvin), NACTUAL = the ideality factor of the on-die thermal diode, NTRIM = the assumed ideality used by the thermal sensor. For the range of temperature where the thermal diode is being measured, 30 - 80° C, this error term is nearly constant.
Thermal Management Logic and Thermal Monitor 4.2.9 How On-Die Thermal Diode, TCONTROL and Thermal Profile Work Together The Celeron D Processor in the 775-land LGA package thermal specification is comprised of two parameters, TCONTROL and Thermal Profile. The first step is to ensure the thermal solution by design meets the thermal profile. If the system design will incorporate variable speed fan control Intel recommends monitoring the on-die thermal diode to implement acoustic fan speed control.
Intel Enabled Thermal Solutions 5.0 Intel Enabled Thermal Solutions 5.1 Thermal Solution Requirements The thermal performance required for the heatsink is determined by calculating the case-to-ambient thermal characterization parameter, ΨCA, as explained in Section 3.0, “Thermal Metrology” on page 18. This is a basic thermal engineering parameter that may be used to evaluate and compare different thermal solutions in similar boundary conditions.
Intel Enabled Thermal Solutions Figure 8. Thermal Characterization Parameters for Various Operating Conditions 5.2 ATX Form Factor Intel is enabling the following active thermal solutions for the Celeron D Processor in the 775-land LGA package for Embedded Applications in the ATX, similar, or larger form factors. Table 5.
Intel Enabled Thermal Solutions maximum TLA, acoustic requirements, etc.) to meet the processor’s thermal requirements. The entire thermal solution, from heatsink design, chassis configuration, and airflow source, must be optimized for server systems to obtain the best performing solution. Intel has worked with a third-party vendor to enable a heatsink design for the Celeron D Processor in the 775-land LGA package for the 1U form factor.
Intel Enabled Thermal Solutions Figure 10. 1U Thermal Solution Z-Height Constraints 5.4 2U Form Factor Intel has developed a reference thermal solution design for the Celeron D processor in the 775-land LGA package for the 2U form factor. This design was optimized for the 2U form factor within the available volume for the thermal solution.
Intel Enabled Thermal Solutions Figure 12. Case-to-Ambient Thermal Characterization Parameter ΨCA (°C/W) Developers of thermal solutions for the Celeron D processor in the 775-land LGA package must ensure that the solution meets the processor thermal specifications as stated in the processor datasheet and follow the recommended motherboard component keep-out as shown in Figure 37 and Figure 38.
Intel Enabled Thermal Solutions Figure 13. 2U Height Restrictions 5.5 Reference Thermal Mechanical Solution For information regarding the Intel Thermal/Mechanical Reference Design thermal solution and design criteria for the ATX form factor, refer to the Intel Pentium 4 Processor on 90nm Process in the 775-Land LGA Package Thermal Design Guidelines.
Conclusion 6.0 Conclusion As the complexities of today’s microprocessors increase, power dissipation requirements become more exacting. Care must be taken to ensure that the additional power is properly dissipated. Heat can be dissipated using passive heatsinks, fans and/or active cooling devices. Incorporating ducted airflow solutions into the system thermal design can yield additional margin.
LGA775 Socket Heatsink Loading Appendix A LGA775 Socket Heatsink Loading A.1 LGA775 Socket Heatsink Considerations The heatsink clip load is traditionally used for: • Mechanical performance in shock and vibration. — Refer to the Intel Pentium 4 Processor on 90nm Process in the 775-Land LGA Package Thermal Design Guide for information on the structural design strategy for the Intel RCBFH-3 Reference Design heatsink. • Thermal interface performance: — Required preload depends on TIM.
LGA775 Socket Heatsink Loading This board deflection metric provides guidance for mechanical designs that differ from the reference design for ATX/µATX form factor. A.2.2 Board Deflection Metric Definition Board deflection is measured along either diagonal (refer to Figure 14): d = dmax – (d1 + d2)/2 d’ = dmax – (d’1 + d’2)/2 Configurations in which the deflection is measured are defined in Table 6.
LGA775 Socket Heatsink Loading A.2.3 Board Deflection Limits Deflection limits for the ATX/µATX form factor are: d_BOL - d_ref= 0.09 mm and d_EOL - d_ref = 0.15 mm and d’_BOL – d’_ref= 0.09 mm and d_EOL’ – d_ref’ = 0.15 mm Note: The heatsink preload must remain within the static load limits defined in the processor datasheet at all times. Note: Board deflection should not exceed board manufacturer specifications. A.2.
LGA775 Socket Heatsink Loading Note: Board and clip creep modify board deflection over time and depend on board stiffness, clip stiffness, and selected materials. Note: Designers must define the BOL board deflection that will lead to the correct EOL board deflection. Figure 15. Example: Defining Heatsink Preload Meeting Board Deflection Limit A.2.5 Additional Considerations Intel recommends to design to {d_BOL - d_ref = 0.
LGA775 Socket Heatsink Loading Note: The heatsink preload must remain below the maximum load limit of the package at all times. Refer to processor datasheet. Note: Board deflection should not exceed board manufacturer specifications. A.2.5.
Heatsink Clip Load Metrology Appendix B Heatsink Clip Load Metrology B.4 Overview This section describes a procedure for measuring the load applied by the heatsink/clip/fastener assembly to a processor package. This procedure is recommended to verify that the preload is within the design target range for a design, and in different situations. For example: • Heatsink preload for the LGA775 socket. • Quantify preload degradation under bake conditions. B.5 Test Preparation B.5.
Heatsink Clip Load Metrology These steps should preserve the original stack height of the heatsink assembly without affecting the stiffness of the heatsink significantly. Figure 16. Load Cell Installation in Machined Heatsink Base Pocket – Bottom View Package IHS Outline (Top Surface) Heatsink Base Pocket ~ 29 mm [~1.15”] Load Cells Figure 17.
Heatsink Clip Load Metrology Figure 18. Preload Test Configuration Preload Fixture (copper core with milled out pocket) Load Cells (3x) B.5.8 Typical Test Equipment For the heatsink clip load measurement, use test equipment equivalent to that listed in Table 7. Table 7. Typical Test Equipment Item Load cell Notes: 1, 5 Description Honeywell*-Sensotec* Model 13 subminiature load cells, compression only. Select a load range depending on load level being tested. Part Number AL322BL www.sensotec.
Heatsink Clip Load Metrology B.6 Test Procedure Examples The following sections give two examples of load measurement. However, these are not meant to be used in mechanical shock and vibration testing. Any mechanical device used along with the heatsink attach mechanism must be included in the test setup (e.g., backplate, attach to chassis, etc.). Before any test, make sure that the load cell has been calibrated against known loads, following load cell vendor’s instructions. B.6.
Thermal Interface Management Appendix C Thermal Interface Management To optimize a heatsink design, it is important to understand the impact of factors related to the interface between the processor and the heatsink base. Specifically, the bond line thickness, interface material area and interface material thermal conductivity should be managed to realize the most effective thermal solution. C.
Case Temperature Reference Methodology Appendix D Case Temperature Reference Methodology D.10 Objective and Scope This appendix defines a reference procedure for attaching a thermocouple to the IHS of an FC-LGA4 processor package for TC measurement. This procedure takes into account the specific features of the FC-LGA4 package and of the LGA775 socket for which it is intended. It describes the recommended equipment for the reference thermocouple installation, including tools and adhesive part numbers. D.
Case Temperature Reference Methodology Table 9.
Case Temperature Reference Methodology D.14 IHS Groove Cut a groove in the package IHS according to Figure 19. Figure 19.
Case Temperature Reference Methodology The orientation of the groove relative to the package pin 1 indicator (gold triangle in one corner of the package) is shown. Figure 20 for the FC-LGA4 package IHS. Figure 20. IHS Reference Groove on the FC-LGA4 Package IHS Groove Pin Indicator When the processor is installed in the LGA775 socket, the groove is perpendicular to the socket load lever, and on the opposite side of the lever, as shown Figure 21. Figure 21.
Case Temperature Reference Methodology D.15 Thermocouple Attach Procedure D.15.1 Thermocouple Conditioning and Preparation 1. Use a calibrated thermocouple as specified in Section D.12 and Section D.13. 2. Measure the thermocouple resistance by holding both wires on one probe and the tip of the thermocouple to the other probe of the DMM. The measurement should be about~75 ohms for 40-gauge type T thermocouple. 3. Straighten the wire for about 38 mm [1½ inch] from the bead to place it inside the channel.
Case Temperature Reference Methodology 7. Lift the wire at the middle of groove with tweezers and bend the front of wire to place the thermocouple in the channel ensuring the tip is in contact with the end of the channel grooved in the IHS (Figure 24 and Figure 25). Figure 24. Thermocouple Bead Placement (View 1) Figure 25. Thermocouple Bead Placement (View 2) 8. Place the TTV under the microscope unit (similar to the one used in Figure 29) to continue with process.
Case Temperature Reference Methodology Figure 26. Position Bead on Groove Step Kapton* tape Wire section into the groove to prepare for final bead placement Figure 27. Detailed Thermocouple Bead Placement 10. Using the micromanipulator, install the needle near to the end of groove on top of thermocouple. Using the X, Y & Z axes on the arm place the tip of needle on top of the thermocouple bead. Press down until the bead is seated at the end of groove on top of the step (see Figure 27 and Figure 28).
Case Temperature Reference Methodology Figure 28. Using 3D Micromanipulator to Secure Bead Location 11. Measure resistance from thermocouple end wires (hold both wires to a DMM probe) to the IHS surface. This should be the same value as measured during the thermocouple conditioning step (Figure 29). Figure 29. Measuring Resistance between Thermocouple and IHS 12. Place a small amount of Loctite* 498 adhesive in the groove where the bead is installed.
Case Temperature Reference Methodology Figure 30. Applying the Adhesive on the Thermocouple Bead 13. Measure the resistance from the thermocouple end wires again using the DMM to ensure the bead is still properly contacting the IHS. D.15.3 Curing Process 1. Let the thermocouple attach set in the open-air for at least half an hour. It is not recommended to use any curing accelerator for this step, as rapid contraction of the adhesive during curing may weaken bead attach on the IHS. 2.
Case Temperature Reference Methodology 5. Using a blade to shave excess adhesive above the IHS surface (Figure 32). Note: Take usual precautions when using open blades. Figure 32. Removing Excess Adhesive from IHS 6. Install new Kapton* tape to hold the thermocouple wire down and fill the rest of groove with adhesive (See Figure 33). Make sure the wire and insulation is entirely within the groove and below the IHS surface. Figure 33.
Board Level PWM and Fan Speed Control Requirements Appendix E Board Level PWM and Fan Speed Control Requirements To utilize all of the features in the Intel reference heatsink design or the Intel boxed processor design, system integrators should verify the following functionality is present in the board design. Please refer to the Fan Specification for 4-Wire PWM Controlled Fans. Requirements Classification: • Required – an essential part of the design necessary to meet specifications.
Mechanical Drawings Appendix F Mechanical Drawings The following table lists the mechanical drawings included in this appendix. These drawings refer to the reference thermal mechanical enabling components for the Intel Celeron D Processor in the 775-Land LGA Package. Note: Intel reserves the right to make changes and modifications to the design as necessary. Table 10.
Mechanical Drawings Figure 34.
Mechanical Drawings Figure 35.
Mechanical Drawings Figure 36.
Mechanical Drawings Figure 37.
Mechanical Drawings Figure 38.
Vendor Information Appendix G Vendor Information This appendix includes supplier information for Intel enabled vendors for the Intel Celeron D Processor in the 775-Land LGA Package thermal solutions. Table 11 lists suppliers that produce Intel enabled reference components. The part numbers listed below identifies these reference components. End-users are responsible for the verification of the Intel enabled component offerings with the supplier.
