JAJSAR0B March 2007 – October 2017 LM95214
PRODUCTION DATA.
To compensate for the errors introduced by non-ideality, the temperature sensor is calibrated for a particular processor. Texas Instruments temperature sensors are always calibrated to the typical non-ideality and series resistance of a given transistor type. The LM95214 is calibrated for the non-ideality factor and series resistance values of the MMBT3904 transistor without the requirement for additional trims. When a temperature sensor calibrated for a particular thermal diode type is used with a different thermal diode type, additional errors are introduced.
Temperature errors associated with non-ideality of different processor types may be reduced in a specific temperature range of concern through use of software calibration. Typical Non-ideality specification differences cause a gain variation of the transfer function, therefore the center of the temperature range of interest must be the target temperature for calibration purposes. The Equation 7 can be used to calculate the temperature correction factor (TCF) required to compensate for a target non-ideality differing from that supported by the LM95214.
where
The correction factor must be directly added to the temperature reading produced by the LM95214. For example when using the LM95214, with the 3904 mode selected, to measure a AMD Athlon processor, with a typical non-ideality of 1.008, for a temperature range of 60°C to 100°C the correction factor would calculate to:
Therefore, 1.75°C must be subtracted from the temperature readings of the LM95214 to compensate for the differing typical non-ideality target.