Intel Xeon Processor 2.80 GHz Thermal/Mechanical Design Guidelines

Thermal/Mechanical Reference Design

36 Dual-Core Intel

Xeon

Processor 2.80 GHz Thermal/Mechanical Design Guidelines

2.4.8 Boxed Active Thermal Solution for the

Dual-Core Intel Xeon Processor 2.80 GHz

In addition to the 1U and 2U passive CEK heatsinks, Intel is developing an active heatsink

solution. This heatsink solution is primarily designed to be used in a pedestal chassis where

sufficient air inlet space is present and side directional airflow is not an issue. All three heatsinks

will be offered as part of boxed Dual-Core Intel Xeon processor 2.80 GHz products. These

solutions are intended for system integrators who build systems from components available

through distribution channels. The retention solution used for these products is called the Common

Enabling Kit, or CEK. The CEK base is compatible with all three heatsink solutions.

Figure 2-17 provides a representation of the active CEK solution. This design is based on a 4-pin

PWM/T-diode controlled active fan heatsink solution. This new solution is being offered to help

provide better control over pedestal chassis acoustics. This is achieved though accurate

measurement of processor temperature through the processor’s temperature diode (T-diode). Fan

RPM is modulated through the use an ASIC located on the serverboard, that sends out a PWM

control signal to the 4th pin of the connector labeled as Control.

This heatsink solution also requires a constant +12 V supplied to pin 2 and does not support

variable voltage control or 3-pin PWM control. If no PWM signal is detected on the 4

pin this

heatsink solution will revert back to thermistor control mode, supporting both the 4-wire PWM and

standard 3-wire ambient air control methods.

Intel may make changes to specification and product descriptions at any time, without notice. The

active heatsink solution will not exceed a mass of approximately 1150 grams. Note that this is per

processor, so a dual processor system will have up to approximately 2300 grams total mass in the

heatsinks. This large mass will require a minimum chassis stiffness to be met in order to withstand

force during shock and vibration. Please refer to Chassis Strength and Stiffness Measurement and

Improvement Guidelines, for Direct Chassis Attach Solutions for more details on chassis

requirements.

Clearance is required around the heatsink to ensure unimpeded airflow for proper cooling. The

physical baseboard keepout requirements for the active solution are the same as the passive CEK

solution shown in Appendix A.

Figure 2-17. Boxed Active CEK Heatsink Solutions with PWM/T-diode Control

(Representation Only)