ADT7476 Datasheet | Analog Devices

FEATURES Monitors up to 5 voltages Controls and monitors up to 4 fans High and low frequency fan drive signal 1 on-chip and 2 remote temperature sensors Extended temperature measurement range up to 191°C Automatic fan speed control mode controls system cooling based on measured temperature Enhanced acoustic mode dramatically reduces user perception of changing fan speeds Thermal protection feature via THERM output Monitors performance impact of Intel® Pentium™ 4 processor Thermal control circuit via THERM input 3-wire and 4-wire fan speed measurement Limit parison of all monitored values Meets SMBus 2.0 electrical specifications GENERAL DESCRIPTION The ADT7476 d BCool controller is a thermal monitor and multiple PWM fan controller for noise-sensitive or powersensitive applications requiring active system cooling. The ADT7476 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 ADT7476 also provides critical thermal protection to the system using the bidirectional THERM pin as an output to prevent system or ponent overheating. FUNCTIONAL BLOCK DIAGRAM ADDREN VID5 VID4/GPIO4 VID3/GPIO3 VID2/GPIO2 VID1/GPIO1 VID0/GPIO0 GPIO6 PWM1 PWM2 PWM3 TACH1 TACH2 TACH3 TACH4 PWM REGISTERS AND CONTROLLERS (HF AND LF) ADDR SELECT SCL SDA SMBALERT VID/GPIO REGISTER SMBus ADDRESS SELECTION SERIAL BUS INTERFACE ADDRESS POINTER REGISTER AUTOMATIC FAN SPEED CONTROL PWM CONFIGURATION REGISTERS INTERRUPT MASKING FAN SPEED COUNTER PERFORMANCE MONITORING THERM VCC TO ADT7476 THERMAL PROTECTION ACOUSTIC ENHANCEMENT CONTROL INPUT SIGNAL CONDITIONING AND ANALOG MULTIPLEXER...