Thermal Specifications
between ntrim and the actual ideality of the particular processor will be calculated. This
value (Tdiode_Offset) will be programmed into the new diode correction MSR and then
added to the Tdiode_Base value can be used to correct temperatures read by diode
based temperature sensing devices.
If the ntrim value used to calculating Tdiode_Offset differs from the ntrim value used in a
temperature sensing device, the Terror(nf) may not be accurate. If desired, the
Tdiode_Offset can be adjusted by calculating nactual and then recalculating the offset
using the actual ntrim as defined in the temperature sensor manufacturers’ datasheet.
The parameters used to calculate the Thermal Diode (Tdiode) Correction Factor are
listed in Table 6-12. For Dual-Core Intel Xeon Processor 5000 series, the range of
Tdiode Correction Factor is ±14°C.
.
Table 6-9.
Thermal Diode Parameters using Diode Model
Symbol
Parameter
Min
Typ
Max
Unit
Notes
I
Forward Bias Current
Diode Ideality Factor
Series Resistance
5
-
200
1.050
6.24
µA
-
1
FW
n
1.000
2.79
1.009
4.52
2, 3, 4
2, 3, 5
R
T
Ω
Notes:
1.
2.
3.
4.
Intel does not support or recommend operation of the thermal diode under reverse bias.
Characterized across a temperature range of 50-80°C.
Not 100% tested. Specified by design characterization.
The ideality factor, n, represents the deviation from ideal diode behavior as exemplified by the diode
qVD/nkT
equation: I
= I * (e
- 1)
FW
S
Where I = saturation current, q = electronic charge, V = voltage across the diode, k = Boltzmann
S
D
Constant, and T = absolute temperature (Kelvin).
5.
The series resistance, R , is provided to allow for a more accurate measurement of the junction
T
temperature. R , as defined, includes the lands of the processor but does not include any socket resistance
T
or board trace resistance between the socket and external remote diode thermal sensor. R can be used by
T
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:
Terror = [R * (N-1) * I min] / [nk/q *ln N]
T
FW
Where Terror=sensor temperature error, N=sensor current ratio, k=Boltzmann Constant, q=electronic
charge.
80
Dual-Core Intel® Xeon® Processor 5000 Series Datasheet
INTEL [ INTEL ]
