Thermal Specifications and Design Considerations
Table 5-6.
Thermal “Diode” Parameters using Transistor Model
Symbol
IFW
Parameter
Min
Typ
Max
Unit
Notes
Forward Bias Current
Emitter Current
5
—
—
200
200
µA
1, 2
IE
5
nQ
Transistor Ideality
0.997
0.391
2.79
1.001
—
1.005
0.760
6.24
-
3, 4, 5
3, 4
Beta
RT
Series Resistance
4.52
Ω
3, 6
NOTES:
1.
2.
3.
4.
5.
Intel does not support or recommend operation of the thermal diode under reverse bias.
Same as IFW in Table 5-5.
Preliminary data. Will be characterized across a temperature range of 50–80 °C.
Not 100% tested. Specified by design characterization.
The ideality factor, nQ, represents the deviation from ideal transistor model behavior as
exemplified by the equation for the collector current:
C = IS * (e qV /n kT –1)
BE
Q
I
Where IS = saturation current, q = electronic charge, VBE = voltage across the transistor
base emitter junction (same nodes as VD), k = Boltzmann Constant, and T = absolute
temperature (Kelvin).
The series resistance, RT, provided in the Diode Model Table (Table 5-5) can be used for
more accurate readings as needed.
6.
The Intel Core2 Extreme processor X6800 and Intel Core2 Duo desktop processor
E6000 and E4000 sequences do not support the diode correction offset that exists on
other Intel processors.
Table 7.
Thermal Diode Interface
Signal
Signal Name
Land Number
Description
THERMDA
THERMDC
AL1
AK1
diode anode
diode cathode
5.4
Platform Environment Control Interface (PECI)
5.4.1
Introduction
PECI offers an interface for thermal monitoring of Intel processor and chipset
components. It uses a single wire, thus alleviating routing congestion issues.
Figure 5-6 shows an example of the PECI topology in a system. PECI uses CRC
checking on the host side to ensure reliable transfers between the host and client
devices. Also, data transfer speeds across the PECI interface are negotiable within a
wide range (2 Kbps to 2 Mbps). The PECI interface on the processor is disabled by
default and must be enabled through BIOS. More information on this can be found in
the Conroe BIOS Writer’s Guide.
Dual-Core Intel® Xeon® Processor 3000 Series Datasheet
85
INTEL [ INTEL ]
