LGA775 Socket Heatsink Loading
16
Thermal and Mechanical Design Guidelines
2.1.2.3
Additional Guidelines
In addition to the general guidelines given above, the heatsink attach mechanism for
the processor should be designed to the following guidelines:
•
Holds the heatsink in place under mechanical shock and vibration events and
applies force to the heatsink base to maintain desired pressure on the thermal
interface material. Note that the load applied by the heatsink attach mechanism
must comply with the package specifications described in the processor datasheet.
One of the key design parameters is the height of the top surface of the processor
IHS above the motherboard. The IHS height from the top of board is expected to
vary from 7.517 mm to 8.167 mm. This data is provided for information only, and
should be derived from:
⎯
The height of the socket seating plane above the motherboard after reflow,
given in the LGA775 Socket Mechanical Design Guide with its tolerances
⎯
The height of the package, from the package seating plane to the top of the
IHS, and accounting for its nominal variation and tolerances that are given in
the corresponding processor datasheet.
•
Engages easily, and if possible, without the use of special tools. In general, the
heatsink is assumed to be installed after the motherboard has been installed into
the chassis.
•
Minimizes contact with the motherboard surface during installation and actuation
to avoid scratching the motherboard.
2.2
Thermal Requirements
Refer to the datasheet for the processor thermal specifications. The majority of
processor power is dissipated through the IHS. There are no additional components,
e.g., BSRAMs, which generate heat on this package. The amount of power that can
be dissipated as heat through the processor package substrate and into the socket is
usually minimal.
The thermal limits for the processor are the Thermal Profile and T
CONTROL
. The Thermal
Profile defines the maximum case temperature as a function of power being
dissipated. T
CONTROL
is a specification used in conjunction with the temperature
reported by the digital thermal sensor and a fan speed control method. Designing to
these specifications allows optimization of thermal designs for processor performance
and acoustic noise reduction.
2.2.1
Processor Case Temperature
For the processor, the case temperature is defined as the temperature measured at
the geometric center of the package on the surface of the IHS. For illustration,
Figure 2 shows the measurement location for a 37.5 mm x 37.5 mm [1.474 in x 1.474
in] 775-Land LGA processor package with a 28.7 mm x 28.7 mm [1.13 in x 1.13 in]
IHS top surface. Techniques for measuring the case temperature are detailed in
Section
3.4.
Note:
In case of conflict, the package dimensions in the processor datasheet supersedes
dimensions provided in this document.
Summary of Contents for QX68000 Core 2 Extreme
Page 30: ...LGA775 Socket Heatsink Loading 30 Thermal and Mechanical Design Guidelines...
Page 74: ...Heatsink Clip Load Metrology 74 Thermal and Mechanical Design Guidelines...
Page 76: ...Thermal Interface Management 76 Thermal and Mechanical Design Guidelines...
Page 96: ...Case Temperature Reference Metrology 96 Thermal and Mechanical Design Guidelines...
Page 108: ...Legacy Fan Speed Control 108 Thermal and Mechanical Design Guidelines...
Page 112: ...BTX System Thermal Considerations 112 Thermal and Mechanical Design Guidelines...
