251308-008 Datasheet, PDF (85/91 Pages) Intel Corporation – Mobile Intel Celeron Processor on .13 Micron Process and in FCPGA Package

Thermal Specifications and Design Considerations
and time based variations in the die temperature. Time based variations can occur since the
sampling rate of the sensor is much slower than the die level temperature changes.
The offset between the thermal diode based temperature reading and the hottest location of the die
(thermal monitor) may be characterized using the thermal monitor’s Automatic mode activation of
thermal control circuit. This temperature offset must be taken into account when using the
processor thermal diode to implement power management events.
Table 37. Thermal Diode Interface
Signal Name
THERMDA
THERMDC
Pin/Ball Number
B3
C4
Signal Description
Thermal diode anode
Thermal diode cathode
Table 38. Thermal Diode Specifications
Symbol
I_FW
n
R_T
Parameter
Forward Bias Current
Diode Ideality Factor
Series Resistance
Min
5
1.0012
Typ
1.0021
3.86
Max
300
1.0030
Unit
µA
ohms
Notes
1
2, 3, 4
2, 3, 5
NOTES:
1. Intel does not support or recommend operation of the thermal diode under reverse bias.
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_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 diode junction
temperature. R_T as defined includes the pins of the processor but does not include any socket resistance or
board trace resistance between the socket and the 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:
T_error = [R_T*(N-1)*I_FWmin]/[(nk/q)*ln N]
Where T_error = sensor temperature error, N = sensor current ration, k = Boltzmann Constant, q = electronic
charge.
6.1.2
Thermal Monitor
The thermal monitor feature found in the mobile Celeron processor allows system designers to
design lower cost thermal solutions without compromising system integrity or reliability. By using
a factory-tuned, precision on-die thermal sensor, and a fast acting thermal control circuit (TCC),
the processor, without the aid of any additional software or hardware, can keep the processor’s die
temperature within factory specifications under nearly all conditions. Thus, the thermal monitor
allows the processor and system thermal solutions to be designed much closer to the power
envelopes of real applications instead of being designed to the much higher maximum processor
power envelopes.
Datasheet
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