This part is a kind of semiconductor called ADT7463.

Function of this product has Remote Thermal Controller and Voltage Monitor.

Manufacturers : ON Semiconductor

Image and pinout :

Some of the text within the PDF file :

ADT7463 Remote Thermal Controller and Voltage Monitor The ADT7463 controller is a complete systems monitor and multiple PWM fan controller for noise−sensitive applications requiring active system cooling. It can monitor 12 V, 5 V, and 2.5 V CPU supply voltages, plus its own supply voltage. It can monitor the temperature of up to two remote sensor diodes, plus its own internal temperature. It can measure and control the speed of up to four fans so that they operate at the lowest possible speed for minimum acoustic noise. The automatic fan speed control loop optimizes fan speed for a given temperature. A unique dynamic TMIN control mode enables the system thermals/acoustics to be intelligently managed. The effectiveness of the system’s thermal solution can be monitored using the THERM i [ ... ]

ADT7463 PDF Datasheet Download