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 active-low FAN_FAIL output is asserted.The 2-wire serial interface accepts standard system management bus (SMBus™) write byte, read byte, send byte, and receive byte commands to read the temperature data and program the alarm thresholds. The programmable alarm output can be used to generate interrupts, throttle signals, or overtemperature shutdown signals.The MAX6616 features six GPIOs to provide additional flexibility. All of the GPIOs power-up as inputs, with the exception of GPIO0, which powers up as either an input or an output as determined by connecting the PRESET pin to ground or VCC.The MAX6616 is available in a 24-pin QSOP package, while the MAX6615 is available in a 16-pin QSOP package. Both devices operate from a single-supply voltage range of 3.0V to 5.5V, have operating temperature ranges of -40°C to +125°C, and consume just 500µA of supply current.ApplicationsDesktop ComputersNetworking EquipmentPower SuppliesServersWorkstations