Datasheet

Thermal Specifications
80 Dual-Core Intel® Xeon® Processor 5000 Series Datasheet
between n
trim
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 n
trim
value used to calculating Tdiode_Offset differs from the n
trim
value used in a
temperature sensing device, the T
error(nf)
may not be accurate. If desired, the
Tdiode_Offset can be adjusted by calculating n
actual
and then recalculating the offset
using the actual n
trim
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.
.
Notes:
1. Intel does not support or recommend operation of the thermal diode under reverse bias.
2. 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
qVD/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 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:
Terror = [R
T
* (N-1) * I
FW
min] / [nk/q *ln N]
Where Terror=sensor temperature error, N=sensor current ratio, k=Boltzmann Constant, q=electronic
charge.
Table 6-9. Thermal Diode Parameters using Diode Model
Symbol Parameter Min Typ Max Unit Notes
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