Datasheet

Datasheet 101
Boxed Processor Specifications
If the boxed processor fan heatsink 4-pin connector is connected to a 4-pin
motherboard header and the motherboard is designed with a fan speed controller with
PWM output (CONTROL see Table 34) and remote thermal diode measurement
capability the boxed processor will operate as follows:
As processor power has increased the required thermal solutions have generated
increasingly more noise. Intel has added an option to the boxed processor that allows
system integrators to have a quieter system in the most common usage.
The 4th wire PWM solution provides better control over chassis acoustics. This is
achieved by more accurate measurement of processor die temperature through the
processor's temperature diode (T-diode). Fan RPM is modulated through the use of an
ASIC located on the motherboard that sends out a PWM control signal to the 4th pin of
the connector labeled as CONTROL. The fan speed is based on actual processor
temperature instead of internal ambient chassis temperatures.
If the new 4-pin active fan heat sink solution is connected to an older 3-pin baseboard
CPU fan header it will default back to a thermistor controlled mode, allowing
compatibility with existing 3-pin baseboard designs. Under thermistor controlled mode,
the fan RPM is automatically varied based on the Tinlet temperature measured by a
thermistor located at the fan inlet.
For more details on specific motherboard requirements for 4-wire based fan speed
control see the appropriate Thermal and Mechanical Design Guidelines (see
Section 1.2).
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Table 35. Fan Heatsink Power and Signal Specifications
Boxed Processor Fan
Heatsink Set Point (
ºC)
Boxed Processor Fan Speed Notes
X ≤ 30
When the internal chassis temperature is below or equal to
this set point, the fan operates at its lowest speed.
Recommended maximum internal chassis temperature for
nominal operating environment.
1
NOTES:
1. Set point variance is approximately ± 1 °C from fan heatsink to fan heatsink.
Y = 35
When the internal chassis temperature is at this point, the
fan operates between its lowest and highest speeds.
Recommended maximum internal chassis temperature for
worst-case operating environment.
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Z ≥ 38
When the internal chassis temperature is above or equal to
this set point, the fan operates at its highest speed.
-