The MAX6615/MAX6616 monitor two temperature channels, either the internal die temperature and the temperature of an external thermistor, or the temperatures of two external thermistors. The temperature data controls a PWM output signal to adjust the speed of a cooling fan, thereby minimizing noise when the system is running cool, but providing maximum cooling when power dissipation increases. The fans' tachometer output signals are monitored by the MAX6615/MAX6616 to detect fan failure. If a fan failure is detected, the FAN_FAIL output is asserted.