LM90,datasheet,pdf(Temperature

The LM90 is an 11-bit digital temperature sensor with a
2-wire System Management Bus (SMBus) serial interface.
The LM90 accurately measures its own temperature as well
as the temperature of an external device, such as processor
thermal diode or diode connected transistor such as the
2N3904. The temperature of any ASIC can be accurately
determined using the LM90 as long as a dedicated diode
(semiconductor junction) is available on the target die. The
LM90 remote sensor accuracy of ±3°C is factory trimmed for
the 1.008 typical non-ideality factor of the mobile Pentium™
III thermal diode. The LM90 has an Offset
register to allow measuring other diodes without
requiring continuous software management. Contact
 to obtain the latest data for
new processors.