ADM1021A
Low Cost Microprocessor
System Temperature
Monitor Microcomputer
The ADM1021A is a two-channel digital thermom...
ADM1021A
Low Cost Microprocessor
System Temperature
Monitor Microcomputer
The ADM1021A is a two-channel digital thermometer and under/overtemperature alarm, intended for use in personal computers and other systems requiring thermal monitoring and management. The device can measure the temperature of a microprocessor using a diode-connected
PNP transistor, which can be provided on-chip with the Pentium III or similar processors, or 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.
The ADM1021A communicates over a two-wire serial interface compatible with SMBus standards. Under/overtemperature limits can be programmed into the device over the serial bus, and an ALERT output signals w...