Intel T5470 LF80537GG0252M Data Sheet

Datasheet

109

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).

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 

I

FW

Forward Bias Current

5

—

200

μA

1

I

E

Emitter Current

5

—

200

μA

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

Ω

2