Thermal Sensor Placement Guidelines; Figure 62. Ddr Memory Thermal Sensor Placement - Intel 852GM Design Manual

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7.7.3.

Thermal Sensor Placement Guidelines

The many factors that can affect the accuracy of ambient temperature measurements by thermal sensors
make the placement of them a very critical and especially challenging task. Ideally, one thermal sensor
should be placed near each SO-DIMM in a system. The thermal sensor should be located in an area
where the effects of airflow and effects of conduction from adjacent components are minimized. This
allows for the best correlation of thermal sensor temperature to chassis or notebook surface temperature.
See Figure 62 for details.
Assuming airflow is negligible within a system, the optimal placement of the thermal sensor is on the
surface of the motherboard directly beneath the shadow of an SO-DIMM module centered longitudinally
and laterally in relation to the outline of the SO-DIMM. The thermal sensor should have a form factor
small enough to allow it to fit beneath double-sided memory modules (i.e. modules with memory
devices on both sides of a module). If placement within the outline of an SO-DIMM is not possible, then
the next best option is to locate it within approximately 15 mm (0.6 inches) of the outline/SO-DIMM
shadow. Again, this assumes negligible effects from airflow.

Figure 62. DDR Memory Thermal Sensor Placement

Hashed Area: Hashed Area:
Recommended area for Recommended area for
DRAM ETS# sensor on DRAM ETS# sensor on
motherboard. motherboard.
Best Location is sensor Best Location is sensor
under S0-DIMM. May not under S0-DIMM. May not
be mechanically feasible in be mechanically feasible in
all designs due to small all designs due to small
gap between SO-DIMM gap between SO-DIMM
and motherboard. and motherboard.
Sensor location within approx 15mm of Sensor location within approx 15mm of
SO-DIMM outline will be not be as SO-DIMM outline will be not be as
effective at controlling fast transient effective at controlling fast transient
temperature changes temperature changes
®
Intel 852GM Chipset Platform Design Guide
System Memory Design Guidelines (DDR-SDRAM)
15mm 15mm 15mm
15mm 15mm 15mm
Top View – SO-DIMM Top View – SO-DIMM
Side View – SO-DIMM Side View – SO-DIMM
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