Intel 2 Duo T5600 LE80537GF0342M User Manual

Datasheet

87

NOTES:
1.

Intel does not support or recommend operation of the thermal diode under reverse bias. 

2.

Same as I

FW 

3.

Characterized across a temperature range of 50-100 °C.

4.

Not 100% tested. Specified by design characterization.

5.

The ideality factor, n

Q

, represents the deviation from ideal diode 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).

6.

The series resistance, R

TT

, provided in the Diode Model Table (

) can be used for 

more accurate readings as needed.

When calculating a temperature based on the thermal diode measurements, a number 

of parameters must be either measured or assumed. Most devices measure the diode 

ideality and assume a series resistance and ideality trim value, although are capable of 

also measuring the series resistance. Calculating the temperature is then accomplished 

using the equations listed under 

. In most sensing devices, an expected value 

for the diode ideality is designed-in to the temperature calculation equation. If the 

designer of the temperature sensing device assumes a perfect diode, the ideality value 

(also called n

trim

) will be 1.000. Given that most diodes are not perfect, the designers 

usually select an n

trim

 value that more closely matches the behavior of the diodes in 

the processor. If the processor diode ideality deviates from that of the n

trim, 

each 

calculated temperature will be offset by a fixed amount. This temperature offset can be 

calculated with the equation:

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.

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, 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-

I

FW

Forward Bias Current

5

200

µA

1, 2

I

E

Emitter Current

5

200

µA

1

n

Q

Transistor Ideality

0.997

1.001

1.005

3, 4, 5

Beta

0.3

0.760

3, 4

R

TT

Series Resistance

2.79

4.52

6.24

Ω

3, 6