Intel BX80532PG3200D, Datasheet

Page: 70 / 74

Thermal Specifications and Design Considerations
70 Datasheet
NOTES:
1.
Intel does not support or recommend operation of the thermal diode under reverse bias.
2. Characterized across a temperature range of 50-105°C.
3. Not 100% tested. Specified by design characterization.
4. The ideality factor, nQ, represents the deviation from ideal transistor model behavior as
exemplified by the equation for the collector current:
I
C
= I
S
* (e
qV
BE
/n
Q
kT
–1)
where I
S
= saturation current, q = electronic charge, V
BE
= voltage across the transistor
base emitter junction (same nodes as VD), k = Boltzmann Constant, and T = absolute
temperature (Kelvin)
.
5.1.2 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.
With a properly designed and characterized thermal solution, 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.
The Intel Thermal Monitor controls the processor temperature by modulating (starting
and stopping) the processor core clocks or by initiating an Enhanced Intel SpeedStep
Technology transition 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 (TM1) and Intel Thermal
Monitor 2 (TM2). 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.
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
Table 15. Thermal Diode Parameters Using Transistor Model
Symbol Parameter Min Typ Max Unit Notes
I
FW
Forward Bias Current 5 — 200  A 1
I
E
Emitter Current 5 — 200  A 1
n
Q
Transistor Ideality 0.997 1.001 1.008 2, 3, 4
Beta 0.1 0.4 0.5 2, 3
R
T
Series Resistance 3.0 4.5 7.0  2