Table of Contents
Advertisement
5.1.2
Thermal Diode Offset
A temperature offset value (specified as Toffset in
Pentium M Processor Model Specific Register (MSR). This offset is determined by using a thermal
diode ideality factor mean value of n = 1.0022 (shown in
be applied to the junction temperature read by the thermal diode. Any temperature adjustments due
to differences between the reference ideality value of 1.0022 and the default ideality values
programmed into the on-board thermal sensors, will have to be made before the above offset is
applied.
Table 5-2. Thermal Diode Interface
Table 5-3. Thermal Diode Specification
Symbol
I
FW
Toffset
n
R
T
NOTES:
1. Intel does not support or recommend operation of the thermal diode under reverse bias. Intel does not
support or recommend operation of the thermal diode when the processor power supplies are not within their
specified tolerance range.
2. Characterized at 100 °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
=I
*(e
FW
s
Where I
and T = absolute temperature (Kelvin).
Value shown in the table is not the Pentium M Processor thermal diode ideality factor. It is a reference value
used to calculate the Pentium M Processor thermal diode temperature offset.
5. The series resistance, R
temperature. R
board trace resistance between the socket and the external remote diode thermal sensor. R
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
= [R
error
6. Offset value is programmed in processor Model Specific Register.
Datasheet
Signal Name
THERMDA
THERMDC
Parameter
Forward Bias Current
Thermal diode temperature
offset
Reference Diode Ideality
Factor used to calculate
temperature offset
Series Resistance
(qV
/nkT)
D
-1)
= saturation current, q = electronic charge, V
S
, is provided to allow for a more accurate measurement of the diode junction
T
as defined includes the pins of the processor but does not include any socket resistance or
T
*(N-1)*I
]/[(no/q)*ln N
T
FWmin
Thermal Specifications and Design Considerations
Table
5-3) will be programmed into a
Table
5-3) as a reference. This offset must
Pin/Ball Number
B18
A18
Min
Typ
Max
5
300
-4
11
1.0022
3.06
= voltage across the diode, k = Boltzmann Constant,
D
Signal Description
Thermal diode anode
Thermal diode cathode
Unit
Notes
μA
Note 1
°C
2, 6
Notes 2, 3, 4
Ohms
2, 3, 5
can be used by
T
81
Advertisement
Table of Contents
