Ultra-Simple Fan-Speed Controller

Enables Simple Implementation of Customizable Fan Control with No Software Development or MCU Required

Please check latest availability status for a specific part variant.


The MAX31740 is a sophisticated, yet easy-to-use fan-speed controller. It monitors the temperature of an external NTC thermistor and generates a PWM signal that can be used to control the speed of a 2-, 3-, or 4-wire fan. The fan control characteristics are set using external resistors, thereby eliminating the need for an external microcontroller. Controllable characteristics include the starting temperature for fan control, PWM frequency, fan speed at low temperatures, and slope of the temperature-duty-cycle transfer function.

Because the operating characteristics are selected by hardwired passive components, a simple, low-cost fan-speed controller can be implemented without the need for firmware development. This can dramatically reduce development time for the fan control function.

The MAX31740 is available in a 2mm x 3mm, 8-pin TDFN package.

MAX31740: Typical Application Circuits MAX31740: Typical Application Circuits Enlarge+

Key Features

  • Self-Contained PWM Fan Control—No Micro Needed
  • Controls Speed of 2-, 3-, or 4-Wire Fans
  • Resistors Set Fan Control Characteristics
  • Smooth, Linearly Varying PWM Duty Cycle Minimizes Audibility of Fan Noise
  • Accurately Monitors External Thermistor Temperature
  • 3.0V to 5.5V Operating Voltage Range
  • -40°C to +125°C Operating Temperature Range


  • Communications Equipment
  • Computing Equipment
  • Consumer Equipment
  • Industrial Equipment
Part NumberSensor TypeFan Cntrl.Temp. Thresh.
See Notes
MAX31740 RemotePWMProgrammable
$0.45 @1k
See All Fan Controllers (22)
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 6500 Temperature Sensor Tutorial

Quality and Environmental Data

Product Reliability Reports: MAX31740.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

CAD Symbols and Footprints

  • MAX31740ATA+
  • MAX31740ATA+T
  • 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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