View max6649 datasheet:

19-2540; Rev 0; 8/02 +145°C Precision SMBus-Compatible Remote/ Local Sensor with Overtemperature Alarms General Description Features The MAX6649 is a precise, two-channel digital temper- Dual Channel: Measures Remote and Local ature sensor. It accurately measures the temperature of Temperature its own die and a remote PN junction, and reports the 0.125°C Resolution temperature in digital form using a 2-wire serial inter- face. The remote PN junction is typically the emitter- High Accuracy ±1°C (max) from +60°C to +145°C base junction of a common-collector PNP on a CPU, (Remote), and ±2°C (max) from +60°C to +100°C FPGA, or ASIC. (Local) The 2-wire serial interface accepts standard System Two Alarm Outputs: ALERT and OVERT Management Bus (SMBus)™ write byte, read byte