The ADT7475 dBCool controller is a thermal monitor and multiple PWM fan controller for noise-sensitive or powersensitive applications requiring active system cooling. The ADT7475 can drive a fan using either a low or high frequency drive signal, monitor the temperature of up to two remote sensor diodes plus its own internal temperature, and measure and control the speed of up to four fans, so they operate at the lowest possible speed for minimum acoustic noise. The automatic fan speed control loop optimizes fan speed for a given temperature. The effectiveness of the system's thermal solution can be monitored using the THERM input. The ADT7475 also provides critical thermal protection to the system using the bidirectional THERM pin as an output to prevent system or component overheating.