This part is a kind of semiconductor called ADM1021A.

Function of this product has Low Cost Microprocessor System Temperature Monitor Microcomputer.

Manufacturers : ON Semiconductor

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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 A [ ... ]

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