Features and Benefits

  • Two Thermal-Diode Inputs
  • Local Temperature Sensor
  • 1°C Remote Temperature Accuracy (+60°C to +100°C)
  • Two PWM Outputs for Fan Drive (Open Drain; can be Pulled Up to +13.5V)
  • Programmable Fan-Control Characteristics
  • Automatic Fan Spin-Up Ensures Fan Start
  • Controlled Rate-of-Change Ensures Unobtrusive Fan-Speed Adjustments
  • ±4% Fan-Speed Measurement Accuracy
  • Temperature Monitoring Begins at POR for Fail-Safe System Protection
  • Active-Low OT and Active-Low THERM Outputs for Throttling or Shutdown
  • Measures Temperatures Up to +150°C
  • Tiny 5mm x 5mm 16-Pin TQFN and QSOP Packages

Product Details

The MAX6640 monitors its own temperature and one external diode-connected transistor or the temperatures of two external diode-connected transistors, typically available in CPUs, FPGAs, or GPUs. The 2-wire serial interface accepts standard System Management Bus (SMBus™) write byte, read byte, send byte, and receive byte commands to read the temperature data and program the alarm thresholds. Temperature data can be read at any time over the SMBus, and three programmable alarm outputs can be used to generate interrupts, throttle signals, or overtemperature shutdown signals.

The temperature data is also used by the internal dual PWM fan-speed controller to adjust the speed of up to two cooling fans, thereby minimizing noise when the system is running cool, but providing maximum cooling when power dissipation increases. Speed control is accomplished by tachometer feedback from the fan, so that the speed of the fan is controlled, not just the PWM duty cycle. Accuracy of speed measurement is ±4%.

The MAX6640 is available in 16-pin QSOP and 16-pin TQFN 5mm x 5mm packages. It operates from 3.0V to 3.6V and consumes just 500µA of supply current.


  • Desktop Computers
  • Networking Equipment
  • Notebook Computers
  • Servers
  • Workstations

Product Categories

Product Lifecycle icon-not-recommended Not Recommended for New Designs

This designates products ADI does not recommend broadly for new designs.

Product Recommendations

MAX6640 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

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