Intel 2 Duo T5600 LE80537GF0342M User Manual

Datasheet

85

The processor incorporates three methods of monitoring die temperature: the digital 

thermal sensor, Intel Thermal Monitor and the thermal “diode.” The Intel Thermal 

Monitor (detailed in 

) must be used to determine when the maximum 

specified processor junction temperature has been reached.

The processor incorporates an on-die PNP transistor whose base emitter junction is 

used as a thermal diode, with its collector shorted to Ground. The thermal diode can be 

read by an off-die analog/digital converter (a thermal sensor) located on the 

motherboard or a stand-alone measurement kit. The thermal diode may be used to 

monitor the die temperature of the processor for thermal management or 

instrumentation purposes but is not a reliable indication that the maximum operating 

temperature of the processor has been reached. When using the thermal diode, a 

temperature offset value must be read from a processor Model Specific Register (MSR) 

and applied. See 

 for more details. Please see 

 for thermal 

diode usage recommendation when the PROCHOT# signal is not asserted.

The reading of the external thermal sensor (on the motherboard) connected to the 

processor thermal diode signals will not necessarily reflect the temperature of the 

hottest location on the die. This is due to inaccuracies in the external thermal sensor, 

on-die temperature gradients between the location of the thermal diode and the hottest 

location on the die, and time based variations in the die temperature measurement. 

Time based variations can occur when the sampling rate of the thermal diode (by the 

thermal sensor) is slower than the rate at which the T

J

 temperature can change. 

Offset between the thermal diode based temperature reading and the Intel Thermal 

Monitor reading may be characterized using the Intel Thermal Monitor’s Automatic 

mode activation of the thermal control circuit. This temperature offset must be taken 

into account when using the processor thermal diode to implement power management 

events. This offset is different than the diode Toffset value programmed into the 

processor MSR. 

 through 

 provides the diode interface and specifications. Two different 

sets of diode parameters are listed in 

. The diode model 

parameters apply to the traditional thermal sensors that use the diode equation to 

determine the processor temperature. Transistor model parameters have been added 

to support thermal sensors that use the transistor equation method. The Transistor 

model may provide more accurate temperature measurements when the diode ideality 

factor is closer to the maximum or minimum limits. Please contact your external sensor 

supplier for their recommendation. The thermal diode is separate from the Intel 

Thermal Monitor’s thermal sensor and cannot be used to predict the behavior of the 

Intel Thermal Monitor.

In order to improve the accuracy of the diode based temperature measurements, a 

temperature offset value (specified as Toffset) will be programmed in the processor 

Model Specific Register (MSR) which will contain thermal diode characterization data. 

During manufacturing each processor thermal diode will be evaluated for its behavior 

relative to the theoretical diode. Using the equation above, the temperature error 

created by the difference n

trim

 and the actual ideality of the particular processor will be 

calculated.