If you are not using the /FANFAIL, /OT, or /ALERT pins, it is ok to leave them unconnected. For /THERM pin, a pull-up resistor on this pin is recommended if D6 of register 13h is enabled since with this…
The equation for this calculation can be found under Table 7 on page 14 of the datasheet. Tach count value = ((internal clock freq.)x 60 / actual RPM) x (selected number of pulses per revolution / actual…
The fan PWM outputs can be toggled to 100% under the following scenarios and conditions:
Scenario 1: The fan PWM outputs are tied to a reference of GND through a resistor to drive a gate.
By default…
The fan PWM outputs can be toggled to 100% under the following scenarios and conditions:
Scenario 1: The fan PWM outputs are tied to a reference of GND through a resistor to drive a gate.
By default…
A 4-pole fan will produce 2 tachometer pulses per revolution. This information is needed in order to calculate the speed of the fan (see Tachometer Pulses per Revolution setting in registers 24h and 25h…
Actual RPM is the measured speed (tachometer counts divided by counts per revolution). Maximum RPM is the rated full speed limitation of the fan. Maximum RPM is the value selected by bits 1:0 in the Fan…
When you are using the PWM to control fan speed by switching on/off the power supply to the fan, using a lower frequency PWM is best, mostly due to noise considerations. When using a PWM to control the…
Pulse Stretching is a feature of some of Maxim's fan controllers, such as MAX6639. The PWM pulses are periodically stretched to keep the tachometer signal available for one full revolution when modulating…
Zeros data in both tachometer count registers (20h-21h) can indicate that the number of tachometer pulses per revolution may have been set incorrectly for those fan motors. A zero value indicates that…
Zeros data in both tachometer count registers (20h-21h) can indicate that the number of tachometer pulses per revolution may have been set incorrectly for those fan motors. A zero value indicates that…
