MAX31785

6-Channel Intelligent Fan Controller

Intelligent Fan Controller Cost-Effectively Improves System Energy Efficiency and Reliability


Please check latest availability status for a specific part variant.

Description

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.
MAX31785: Typical Operating Circuit MAX31785: Typical Operating Circuit Enlarge+

Key Features

  • 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

Applications/Uses

  • Base Stations
  • Industrial Controls
  • Network Switches/Routers
  • Servers
  • Smart Grid Network Systems
Part NumberSensor TypeFan Controller FunctionsFan Cntrl.InterfaceAccuracy
(±°C)
Temp. Thresh.
(°C)
Temp. Resolution
(bits)
Package/PinsBudgetary
Price
See Notes
MAX31785 Remote
Dual Temperature Alarms
Fan Failure Detector
Remote & Local Sensor
Temperature Switch/Temperature Comparator
PWM2-Wire/I2C/SMBus2Programmable12
TQFN/40
$4.75 @1k
See All Fan Controllers (20)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


MAX31785K: Evaluation Kit for the MAX31785

Technical Documents

App Note 5041 Add a "Black Box" Fault Logger to Your "Big (or Small) Box" System

Quality and Environmental Data

Product Reliability Reports: MAX31785.pdf 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >

 
Status:
Package:
Temperature:

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