MAX6639F

2-Channel Temperature Monitor with Dual, Automatic, PWM Fan-Speed Controller

High-Frequency, Dual Temperature Sensor and Fan Controller with Selectable Address and Closed-Loop Operation

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Overview

Two Thermal-Diode Inputs
Up to 25kHz PWM Output Frequency
Three Selectable SMBus Addresses
Local Temperature Sensor
1°C Remote Temperature Accuracy
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
±3% 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
MAX6639F is Optimized for n = 1.021 for Penryn Compatibility

The MAX6639 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 MAX6639 is available in 16-pin QSOP and 16-pin thin QFN 5mm x 5mm packages. It operates from 3.0V to 3.6V and consumes just 500µA of supply current.

Applications

Desktop Computers
Networking Equipment
Notebook Computers
Projectors
Servers

Documentation

Data Sheet 1

MAX6639-MAX6639F: 2-Channel Temperature Monitor with Dual, Automatic, PWM Fan-Speed Controller Data Sheet (Rev.3) 05/06/2013

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Evaluation Kits

Evaluation Kit for the MAX6639 and MAX6639F

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Features and Benefits

Two Thermal-Diode Inputs
Local Temperature Sensor
Programmable Temperature Alarms
Two PWM Outputs for Fan Drive
Up to 25kHz PWM Output Frequency
Programmable Fan-Control Characteristics
3-Wire and 4-Wire Fan Configurations
On-Board Microcontroller to Generate SMBus™ /I²C Commands
USB-PC Connection (Cable Included)
Windows 2000/XP- and Windows Vista (32-Bit)-Compatible Software
Easy-to-Use, Menu-Driven Software
Lead(Pb)-Free and RoHS Compliant
Fully Assembled and Tested

Product Details

The MAX6639 evaluation kit (EV kit) is an assembled and tested PCB used to evaluate the MAX6639 dual temperature sensor/fan controller. The MAX6639 monitors its own die temperature and the junction temperature of one external diode-connected transistor, or the junction temperatures of two external diode-connected transistors. It converts the temperature to 8-bit or 11-bit 2-wire serial data that can be accessed over a 2-wire serial bus.

The MAX6639 EV kit includes both external diode-connected transistors (2N3906) soldered to the board, which can be bypassed to connect the board through a twisted pair to remote diodes close to your system.

The temperature data is also used by the internal dual PWM fan-speed controller to adjust the speed of up to two cooling fans. Speed control is accomplished by tachometer feedback from the fan.

The EV kit also includes Windows® 2000/XP- and Windows Vista®-compatible software, which provides a simple user interface for exercising the features of the MAX6639. The program is menu-driven and offers a graphical user interface (GUI) complete with control buttons. The EV kit comes with the MAX6639AEE+ installed. Contact the factory for free samples of the pin-compatible MAX6639FAEE+ and MAX6640AEE+.

The MAX6639 EV kit also evaluates the MAX6640. The MAX6640 is not recommended for new designs.