Intel 4 HT 631 80552PG0802M2M Data Sheet
Product codes
80552PG0802M2M
Thermal Specifications and Design Considerations
84
Datasheet
accomplished using the equations listed under
. In most temperature 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 processors diode ideality deviates
from that of 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
X (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.
To improve the accuracy of diode based temperature measurements, a new register
(T
diode_Offset
) has been added to processor that will contain thermal diode
characterization data. During manufacturing each processors thermal diode will be
evaluated for its behavior relative to a theoretical diode. Using the equation above, the
temperature error created by the difference between n
trim
and the actual ideality of the
particular processor will be calculated. This value (T
diode_Offset
) will be programmed in
to the new diode correction MSR and when added to the T
diode_Base
value can be used
to correct temperatures read by diode based temperature sensing devices.
If the n
trim
value used to calculate T
diode_Offset
differs from the n
trim
value used in a
temperature sensing device, the T
error(nf)
may not be accurate. If desired, the
T
diode_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 Diode_Base value and n
trim
used to calculate the Diode_Correction_Offset are
listed in
§ §
Table 32.
Thermal “Diode” n
trim
and Diode_Correction_Offset
Symbol
Parameter
Unit
n
trim
Diode ideality used to calculate Diode_Offset
1.008
—
Diode_Base
0
°C
Table 33.
Thermal Diode Interface
Signal Name
Land Number
Signal
Description
THERMDA
AL1
diode anode
THERMDC
AK1
diode cathode