Balanced Technology Extended (BTX) Boxed Processor Specifications
Table 37.
TMA Set Points for 3-wire operation of BTX Type I and Type II Boxed
Processors
Boxed Processor
TMA Set Point
(ºC)
Boxed Processor Fan Speed
Notes
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
X ≤ 23
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.
Y = 29
When the internal chassis temperature is above or equal to this
set point, the fan operates at its highest speed.
1
Z ≥ 35.5
NOTES:
1. Set point variance is approximately ±1°C from Thermal Module Assembly to Thermal Module Assembly.
If the boxed processor TMA 4-pin connector is connected to a 4-pin motherboard
header and the motherboard is designed with a fan speed controller with PWM output
(see CONTROL in Table 36) and remote thermal diode measurement capability, the
boxed processor will operate as described in the following paragraphs.
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 4-wire PWM controlled fan in the TMA solution provides better control over chassis
acoustics. It allows better granularity of fan speed and lowers overall fan speed than a
voltage-controlled fan. 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 a combination of actual processor
temperature and thermistor temperature.
If the 4-wire PWM controlled fan in the TMA solution is connected to a 3-pin baseboard
processor 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 processor Thermal and Mechanical Design Guidelines (see
Section 1.2).
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Datasheet
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INTEL [ INTEL ]
