Thermal Specifications and Design Considerations
Note: The digital thermal sensor (DTS) accuracy is in the order of -5°C ~ +10°C around
90°C; it deteriorates to ±10°C at 50°C. The DTS temperature reading saturates at
some temperature below 50°C. Any DTS reading below 50°C should be considered to
indicate only a temperature below 50°C and not a specific temperature. External
thermal sensor with “BJT” model is required to read thermal diode temperature.
5.3.1
Out of Specification Detection
Overheat detection is performed by monitoring the processor temperature and
temperature gradient. This feature is intended for graceful shut down before the
THERMTRIP# is activated. If the processor’s Intel Thermal Monitor-1 or Intel Thermal
Monitor-2 are triggered and the temperature remains high, an “Out Of Spec” status
and sticky bit are latched in the status MSR register and generates thermal interrupt.
5.3.2
PROCHOT# Signal Pin
An external signal, PROCHOT# (processor hot), is asserted when the processor die
temperature has reached its maximum operating temperature. If Intel Thermal
Monitor-1 or Intel Thermal Monitor-2 is enabled, then the TCC will be active when
PROCHOT# is asserted. The processor can be configured to generate an interrupt
upon the assertion or de-assertion of PROCHOT#.
The processor implements a bi-directional PROCHOT# capability to allow system
designs to protect various components from overheating situations. The PROCHOT#
signal is bi-directional in that it can either signal 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.
Only a single PROCHOT# pin exists at a package level of the processor. When the
core's thermal sensor trips, the PROCHOT# signal will be driven by the processor
package. If only Intel Thermal Monitor-1 is enabled, PROCHOT# will be asserted and
only the core that is above TCC temperature trip point will have its core clocks
modulated. If Intel Thermal Monitor-2 is enabled and the core is above TCC
temperature trip point, it will enter the lowest programmed Intel Thermal Monitor-2
performance state. It is important to note that Intel recommends both Intel Thermal
Monitor-1 and Intel Thermal Monitor-2 to be enabled.
When PROCHOT# is driven by an external agent and if only Intel Thermal Monitor-1 is
enabled on the core, then the processor core will have the clocks modulated. If Intel
Thermal Monitor-2 is enabled, then the processor core will enter the lowest
programmed Intel Thermal Monitor-2 performance state. It should be noted that Force
Intel Thermal Monitor-1 on Intel Thermal Monitor-2, enabled via BIOS, does not have
any effect on external PROCHOT#. If PROCHOT# is driven by an external agent when
Intel Thermal Monitor-1, Intel Thermal Monitor-2, and Force Intel Thermal Monitor-1
on Intel Thermal Monitor-2 are all enabled, then the processor will still apply only Intel
Thermal Monitor-2.
PROCHOT# may be used for 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. By asserting PROCHOT# (pulled-low)
and activating the TCC, the VR will cool down as a result of reduced processor power
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Datasheet
INTEL [ INTEL ]
