Intel G850 CM8062301046204 Data Sheet

Datasheet

81

The processor incorporates an on-die PNP transistor where the base emitter junction is 

used as a thermal "diode", with its collector shorted to ground. A thermal sensor 

located on the system board may monitor the die temperature of the processor for 

thermal management and fan speed control. 

, and 

 provide 

the "diode" parameter and interface specifications. Two different sets of "diode" 

parameters are listed in 

. The Diode Model parameters (

) 

apply to traditional thermal sensors that use the Diode Equation to determine the 

processor temperature. Transistor Model parameters (

) have been added to 

support thermal sensors that use the transistor equation method. The Transistor Model 

may provide more accurate temperature measurements when the diode ideality factor 

is closer to the maximum or minimum limits. This thermal "diode" is separate from the 

Thermal Monitor's thermal sensor and cannot be used to predict the behavior of the 

Thermal Monitor.

T

CONTROL

 is a temperature specification based on a temperature reading from the 

thermal diode. The value for T

CONTROL

 will be calibrated in manufacturing and 

configured for each processor. The T

CONTROL

 temperature for a given processor can be 

obtained by reading a MSR in the processor. The T

CONTROL

 value that is read from the 

MSR needs to be converted from Hexadecimal to Decimal and added to a base value of 

50 °C.

The value of T

CONTROL

 may vary from 00 h to 1E h (0 to 30 °C).

When T

DIODE

 is above T

CONTROL

, then T

C

 must be at or below T

C_MAX

 as defined by the 

thermal profile in 

; otherwise, the processor temperature can be maintained at 

T

CONTROL

 (or lower) as measured by the thermal diode.

NOTES:
1.

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

2.

Preliminary data. Will be characterized across a temperature range of 50 – 80 °C.

3.

Not 100% tested. Specified by design characterization.

4.

The ideality factor, n, represents the deviation from ideal diode behavior as exemplified by 
the diode equation:

I

FW

 = I

S

 * (e 

qV

D

/nkT

 –1)

where I

S

 = saturation current, q = electronic charge, V

D

 = voltage across the diode, k = 

Boltzmann Constant, and T = absolute temperature (Kelvin).

5.

The series resistance, R

T

, is provided to allow for a more accurate measurement of the 

junction temperature. R

T

, as defined, includes the lands of the processor but does not 

include any socket resistance or board trace resistance between the socket and the 
external remote diode thermal sensor. R

T

 can be used by remote diode thermal sensors 

with automatic series resistance cancellation to calibrate out this error term. Another 
application is that a temperature offset can be manually calculated and programmed into 
an offset register in the remote diode thermal sensors as exemplified by the equation:

T

error

 = [R

T

 * (N–1) * I

FWmin

] / [nk/q * ln N]

where T

error

 = sensor temperature error, N = sensor current ratio, k = Boltzmann 

Constant, q = electronic charge. 

I

FW

Forward Bias Current

5

—

200

µA

1

n

Diode Ideality Factor

1.000

1.009

1.050

-

2, 3, 4

R

T

Series Resistance

2.79

4.52

6.24

Ω

2, 3, 5