Intel 530 LF80537NE0301M Data Sheet

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, 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).

6.

The series resistance, R

T

, 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

) is 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 offsets 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.

In order to improve the accuracy of the diode-based temperature measurements, a 

temperature offset value (specified as Toffset) is programmed in the processor MSR 

which contains thermal diode characterization data. During manufacturing each 

processor thermal diode is evaluated for its behavior relative to the theoretical diode. 

Using the equation above, the temperature error created by the difference n

trim

 and the 

actual ideality of the particular processor is calculated.

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

T

Series Resistance

2.79

4.52

6.24

Ω

3,6