DESCRIPTION The ADT7490 is a dBCool thermal monitor and multiple PWM fan controller for noise-sensitive or power-sensitive applications requiring active system cooling. The ADT7490 includes a local temperature sensor, two remote temperature sensors including series resistance cancellation, and monitors CPU temperature with a PECI interface. The ADT7490 can drive a fan using either a low or high frequency drive signal, 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 temperature information. The effectiveness of the system s thermal solution can be monitored using the THERM input. The ADT7490 also provides critical thermal protection to the system using the bidirectional THERM/SMBALERT pin as an output to prevent system or component overheating. ADT7490 Rev. 0 | Page 2 of 76 FUNCTIONAL BLOCK DIAGRAM ACOUSTICENHANCEMENTCONTROLBAND GAPREFERENCE10-BITADCINTE FEATURES Temperature measurement: 1 local on-chip temperature sensor 2 remote temperature sensors 3-current external temperature sensors with series resistance cancellation (SRC) up to 4 PECI inputs on one pin Fan drive and fan speed control 3 high frequency or low frequency PWM outputs for use with 3-wire or 4-wire fans 4 TACH inputs to measure fan speed OS independent automatic fan speed control based on thermal information Dynamic TMIN control mode to optimize system acoustics Default startup at 100% PWM for all fans for robust operation Bidirectional THERM/SMBALERT pin to flag out-of-limit and overtemperature conditions GPIO functionality to support extra features Can be used for loadline setting for voltage regulation, LED control, or other functions IMON monitoring for CPU current and power information Footprint and register compatible with ADT7473/ADT7475/ ADT7476/ADT7476A family of fan controllers SMBus interface with addressing capability for up to 3 devices APPLICATIONS Perso Specifications subject to change without notic