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Datasheet
Thermal Specifications
Refer to the appropriate platform design guidelines for details on implementing the FORCEPR#
signal feature.
6.2.6
THERMTRIP# Signal Pin
Regardless of whether or not Thermal Monitor or Thermal Monitor 2 is enabled, in the event of a
catastrophic cooling failure, the processor will automatically shut down when the silicon has
reached an elevated temperature (refer to the THERMTRIP# definition in
Table 4-1). At this point,
the system bus signal THERMTRIP# will go active and stay active as described in
Table 4-1.
THERMTRIP# activation is independent of processor activity and does not generate any bus
cycles.
6.2.7
TCONTROL and Fan Speed Reduction
Tcontrol is a temperature specification based on a temperature reading from the thermal diode. The
value for Tcontrol will be calibrated in manufacturing and configured for each processor. The
Tcontrol temperature for a given processor can be obtained by reading the
IA32_TEMPERATURE_TARGET MSR in the processor. The Tcontrol value that is read from the
IA32_TEMPERATURE_TARGET MSR must be converted from Hexadecimal to Decimal and
added to a base value. The base value is 50
° C for the 64-bit Intel Xeon processor with 2 MB L2
cache.
The value of Tcontrol may vary from 0x00h to 0x1Eh. Systems that support the 64-bit
Intel Xeon processor with 2 MB L2 cache must implement BIOS changes to detect which
processor is present, and then select from the appropriate Tcontrol_base value.
When Tdiode is above Tcontrol, then TCASE must be at or below TCASE_MAX as defined by the
can be maintained at Tcontrol.
6.2.8
Thermal Diode
The processor incorporates an on-die thermal diode. A thermal sensor located on the system board
may monitor the die temperature of the processor for thermal management/long term die
temperature change purposes.
Table 6-9 and
Table 6-10 provide the diode parameter and interface
specifications. This thermal diode is separate from the Thermal Monitor’s thermal sensor and
cannot be used to predict the behavior of the Thermal Monitor.
NOTES:
1. Intel does not support or recommend operation of the thermal diode under reverse bias.
2. Characterized at 75
° C.
3. Not 100% tested. Specified by design characterization.
4. The ideality factor, n, represents the deviation from ideal diode behavior as exemplified by the diode
equation: IFW = IS * (e
qVD/nkT - 1)
Where IS = saturation current, q = electronic charge, VD = voltage across the diode, k = Boltzmann Constant,
and T = absolute temperature (Kelvin).
Table 6-9. Thermal Diode Parameters
Symbol
Min
Typ
Max
Unit
Notes
IFW
Forward Bias Current
11
187
A1
n
Diode ideality factor
1.0083
1.011
1.0183
2,3,4
RT
Series Resistance
3.242
3.33
3.594
2,3,5