Intel N450 AU80610004653AA User Manual
Product codes
AU80610004653AA
Datasheet
67
Thermal Specifications and Design Considerations
T
error(nf)
= T
measured
* (1 - n
actual
/n
trim
)
where T
error(nf)
is the offset in degrees C, T
measured
is in Kelvin, n
actual
is the
measured ideality of the diode, and n
trim
is the diode ideality assumed by the
temperature sensing device.
6.1.2
Intel® Thermal Monitor
The Intel Thermal Monitor helps control the processor temperature by activating the
TCC (Thermal Control Circuit) when the processor silicon reaches its maximum
operating temperature. The temperature at which the Intel Thermal Monitor activates
the TCC is not user configurable. Bus traffic is snooped in the normal manner and
interrupt requests are latched (and serviced during the time that the clocks are on)
while the TCC is active.
TCC (Thermal Control Circuit) when the processor silicon reaches its maximum
operating temperature. The temperature at which the Intel Thermal Monitor activates
the TCC is not user configurable. Bus traffic is snooped in the normal manner and
interrupt requests are latched (and serviced during the time that the clocks are on)
while the TCC is active.
With a properly designed and characterized thermal solution, it is anticipated that the
TCC would only be activated for very short periods of time when running the most
power intensive applications. The processor performance impact due to these brief
periods of TCC activation is expected to be minor and hence not detectable. An under-
designed thermal solution that is not able to prevent excessive activation of the TCC in
the anticipated ambient environment may cause a noticeable performance loss and
may affect the long-term reliability of the processor. In addition, a thermal solution that
is significantly under designed may not be capable of cooling the processor even when
the TCC is active continuously.
TCC would only be activated for very short periods of time when running the most
power intensive applications. The processor performance impact due to these brief
periods of TCC activation is expected to be minor and hence not detectable. An under-
designed thermal solution that is not able to prevent excessive activation of the TCC in
the anticipated ambient environment may cause a noticeable performance loss and
may affect the long-term reliability of the processor. In addition, a thermal solution that
is significantly under designed may not be capable of cooling the processor even when
the TCC is active continuously.
The Intel Thermal Monitor controls the processor temperature by modulating (starting
and stopping) the processor core clocks when the processor silicon reaches its
maximum operating temperature. The Intel Thermal Monitor uses two modes to
activate the TCC: automatic mode and on-demand mode. If both modes are activated,
automatic mode takes precedence.
and stopping) the processor core clocks when the processor silicon reaches its
maximum operating temperature. The Intel Thermal Monitor uses two modes to
activate the TCC: automatic mode and on-demand mode. If both modes are activated,
automatic mode takes precedence.
There are two automatic modes called Intel Thermal Monitor-1 and Intel Thermal
Monitor-2. These modes are selected by writing values to the MSRs of the processor.
After automatic mode is enabled, the TCC will activate only when the internal die
temperature reaches the maximum allowed value for operation.
Monitor-2. These modes are selected by writing values to the MSRs of the processor.
After automatic mode is enabled, the TCC will activate only when the internal die
temperature reaches the maximum allowed value for operation.
The Intel Thermal Monitor automatic mode must be enabled through BIOS for
the processor to be operating within specifications. Intel recommends TM1
and TM2 be enabled on the processors.
the processor to be operating within specifications. Intel recommends TM1
and TM2 be enabled on the processors.
When TM1 is enabled and a high temperature situation exists, the clocks will be
modulated by alternately turning the clocks off and on at a 50% duty cycle. Cycle times
are processor speed dependent and will decrease linearly as processor core frequencies
increase. Once the temperature has returned to a non-critical level, modulation ceases
and TCC goes inactive. A small amount of hysteresis has been included to prevent rapid
active/inactive transitions of the TCC when the processor temperature is near the trip
point. The duty cycle is factory configured and cannot be modified. Also, automatic
mode does not require any additional hardware, software drivers, or interrupt handling
routines. Processor performance will be decreased by the same amount as the duty
cycle when the TCC is active.
modulated by alternately turning the clocks off and on at a 50% duty cycle. Cycle times
are processor speed dependent and will decrease linearly as processor core frequencies
increase. Once the temperature has returned to a non-critical level, modulation ceases
and TCC goes inactive. A small amount of hysteresis has been included to prevent rapid
active/inactive transitions of the TCC when the processor temperature is near the trip
point. The duty cycle is factory configured and cannot be modified. Also, automatic
mode does not require any additional hardware, software drivers, or interrupt handling
routines. Processor performance will be decreased by the same amount as the duty
cycle when the TCC is active.