Fan Controller/Driver with Factory-Programmed Temperature Thresholds

Please check latest availability status for a specific part variant.


The MAX6665 is a fully integrated thermal switch with an internal power transistor for driving a cooling fan rated up to 24V and 250mA. When the MAX6665's temperature rises above a factory-programmed threshold, the active-low FANOUT pin becomes active and powers the fan.

The MAX6665 is available with factory-programmed fan activation threshold temperatures from +40°C to +70°C in 5°C increments. Accuracy of the fan activation trip point is ±1°C (typ) and ±3°C (max). The trip point's hysteresis is pin selectable to 1°C, 4°C, or 8°C. Two open-drain logic outputs indicate overtemperature con- ditions: active-low WARN is activated when the temperature is 15°C above the fan activation threshold, and OT is activated when the temperature is 30°C above the threshold. These features can be used to safely power down systems that are overheated.

The MAX6665 operates from a +2.7V to +5.5V power supply, and the associated fan can be powered from 4.5V to 24V. It is available in an 8-pin SO package and operates from -40°C to +125°C.
MAX6665: Typical Operating Circuit MAX6665: Typical Operating Circuit Enlarge+

Key Features

  • On-Chip 250mA Fan Switch
  • No External Components Required
  • Factory-Programmed Thresholds
  • Two Overtemperature Warning Signals
  • Pin-Selectable 1°C, 4°C, and 8°C Hysteresis
  • Low 65µA Supply Current


  • Card Racks
  • Laboratory Instruments
  • Notebook and Desktop Computers
  • PC Power Supplies
  • Servers
Part NumberFan Controller FunctionsFan Cntrl.InterfaceAccuracy
Temp. Thresh.
See Notes
MAX6665 Temperature Switch/Temperature ComparatorLinearLogic3Factory Programmed
SOIC (N)/8
$1.59 @1k
See All Fan Controllers (21)
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.

Technical Documents

Tutorial 4679 Thermal Management Handbook

Quality and Environmental Data

Product Reliability Reports: MAX6665.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Additional Resources

Temperature Family by Product Type
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 >


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