The ADM10231 is a 2-channel digital thermometer and underand overtemperature alarm for use in personal computers and other systems requiring thermal monitoring and management. Optimized for the Pentium III, the higher accuracy allows systems designers to safely reduce temperature guard banding and increase system performance. The device can measure the temperature of a microprocessor using a diode-connected PNP transistor, which may be provided on-chip with the Pentium III or similar processors; or it can be a low-cost, discrete NPN/PNP device such as the 2N3904/2N3906. A novel measurement technique cancels out the absolute value of the transistor's base emitter voltage so that no calibration is required. The second measurement channel measures the output of an on-chip temperature sensor to monitor the temperature of the device and its environment.