Intel E6750 Design Guidelines - Page 38

Thermal Management Logic and Thermal Monitor Feature A system designed to meet the thermal profile specification published in the processor datasheet greatly reduces the probability of real applications causing the thermal control circuit to activate under normal operating conditions. Systems that do not meet these specifications could be subject to more frequent activation of the thermal control circuit depending upon ambient air temperature and application power profile. Moreover, if a system is significantly under designed, there is a risk that the Thermal Monitor feature will not be capable of reducing the processor power and temperature and the processor could shutdown and signal THERMTRIP#. For information regarding THERMTRIP#, refer to the processor datasheet and to Section 4.2.8 of this Thermal Design Guidelines. 4.2.7 Operating System and Application Software Considerations The Thermal Monitor feature and its thermal control circuit work seamlessly with ACPI compliant operating systems. The Thermal Monitor feature is transparent to application software since the processor bus snooping, ACPI timer, and interrupts are active at all times. 4.2.8 THERMTRIP# Signal In the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon temperature has exceeded the TCC activation temperature by approximately 20 to 25 °C. At this point the system bus signal THERMTRIP# goes active and power must be removed from the processor. THERMTRIP# activation is independent of processor activity and does not generate any bus cycles. Refer to the processor datasheet for more information about THERMTRIP#. The temperature where the THERMTRIP# signal goes active is individually calibrated during manufacturing and once configuration can not be changed. 4.2.9 4.2.10 Cooling System Failure Warning It may be useful to use the PROCHOT# signal as an indication of cooling system failure. Messages could be sent to the system administrator to warn of the cooling failure, while the thermal control circuit would allow the system to continue functioning or allow a normal system shutdown. If no thermal management action is taken, the silicon temperature may exceed the operating limits, causing THERMTRIP# to activate and shut down the processor. Regardless of the system design requirements or thermal solution ability, the Thermal Monitor feature must still be enabled to ensure proper processor operation. Digital Thermal Sensor Multiple digital thermal sensors can be implemented within the package without adding a pair of signal pins per sensor as required with the thermal diode. The digital thermal sensor is easier to place in thermally sensitive locations of the processor than the thermal diode. This is achieved due to a smaller foot print and decreased sensitivity to noise. Since the DTS is factory set on a per-part basis there is no need for the health monitor components to be updated at each processor family 38 Thermal and Mechanical Design Guidelines