6-Channel Intelligent Fan Controller

The MAX31785 is a closed-loop multichannel fan controller. Automatic closed-loop fan control saves system power by operating the fans at the lowest possible speeds. Added benefits of slower fan speeds include lower audible noise, longer fan life, and reduced system maintenance. Based on a user-programmable lookup table (LUT), the device automatically adjusts the speeds of the six independent fans based on one or more of the 11 available temperature sensors. Alternately, an external host can manually command the fan speeds and the device automatically adjusts the fan speeds. The device contains a fan-health-diagnostic function to help users predict impending fan failures. The device can also monitor up to six remote voltages.

Applications

* Base Stations * Industrial Controls * Network Switches/Routers * Servers * Smart Grid Network Systems

* Six Independent Channels of Fan Control

* Supports 3-Wire and 4-Wire Fans

* Automatic Closed-Loop Fan Speed Control

* RPM- or PWM-Based Control

* Optional Manual Mode Control

* Fast and Slow PWM Frequency Options

* Staggered Fan Spin-Up Eases Power-Supply Stress

* Dual Tachometer (12-Fan Support)

* Fan-Fault Detection

* Fan-Health Status Meter

* Nonvolatile Fan Operating Run Time Meter

* Supports Up to 11 Temperature Sensors

* Up to Six External Thermal Diodes with Automatic Series Resistance Cancellation

* One Internal Temperature Sensor

* Up to Four I²C Digital Temperature Sensors

* Fault Detection on All Temperature Sensors

* Available 6-Channel ADC to Measure Remote Voltages

* PMBus™-Compliant Command Interface

* I²C/SMBus-Compatible Serial Bus with Bus Timeout Function

* On-Board Nonvolatile Fault Logging and Default Configuration Setting

* No External Clocking Required

* +3.3V Supply Voltage