The ADM1032 is a dual-channel digital thermometer and under/over temperature alarm, intended for use in personal computers and thermal management systems. The higher 1C accuracy offered allows systems designers to safely reduce temperature guardbanding and increase system performance. The device can measure the temperature of a microprocessor using a diode-connected NPN or PNP transistor, which may be provided on-chip or can be a low-cost discrete device such as the 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. The ADM1032 communicates over a two-wire serial interface compatible with System Management Bus (SMBus) standards. Under and over temperature limits can be programmed into the device over the serial bus, and an ALERT output signals when the on-chip or remote temperature measurement is out of range. This output can be used as an interrupt, or as an SMBus alert. The THERM output is a comparator output that allows CPU clock throttling or on/off control of a cooling fan.