Intel
®
945G Express Chipset GMCH Thermal Design Guide
Introduction
Term Description
mBGA
Mini ball grid array. A smaller version of the BGA. Wire bonded package with die encased
with a mold encapsulant.
GMCH
Graphic memory controller hub. The chipset component that contains the processor and
memory interface and integrated graphics core.
T
A
The measured ambient temperature locally to the component of interest. The ambient
temperature should be measured just upstream of airflow for a passive heat sink or at the
fan inlet for an active heat sink. Also referred to as T
LA
.
T
C
The measured case temperature of a component. For processors, it is measured at the
geometric center of the integrated heat spreader (IHS). For other component types, it is
generally measured at the geometric center of the top of the die or case.
T
S
The measured temperature of the heat sink. T
S
is measured at a point on the bottom of
the heat sink base that corresponds to the location of the T
C
measurement.
T
C-MAX
The maximum case/die temperature with an attached heat sink. This temperature is
measured at the geometric center of the top of the package case/die.
T
C-MIN
The minimum case/die temperature with an attached heat sink. This temperature is
measured at the geometric center of the top of the package case/die.
TDP
Thermal design power is specified as the highest sustainable power level of most or all of
the real applications expected to be run on the given product, based on extrapolations in
both hardware and software technology over the life of the component. Thermal solutions
should be designed to dissipate this target power level.
TIM
Thermal interface material: thermally conductive material installed between two surfaces
to improve heat transfer and reduce interface contact resistance.
lfm
Linear feet per minute. Unit of airflow speed.
CFM
Cubic feet per minute. Volumetric fluid flow rate.
Ψ
CA
Case-to-ambient thermal characterization parameter (Psi). A measure of thermal solution
performance using total package power. Defined as (T
C
– T
A
) / Total Package Power. Heat
source size should always be specified for
Ψ
measurements.
Ψ
SA
Sink-to-ambient thermal characterization parameter (Psi). A measure of the heat sink
performance using total package power. Defined as (T
S
– T
A
) / Total Package Power.
Heat source size should always be specified for
Ψ
measurements.
Ψ
CS
Case-to-sink thermal characterization parameter (Psi). A measure of the thermal interface
material’s performance using total package power. Defined as (T
C
– T
S
) / Total Package
Power. Heat source size should always be specified for
Ψ
measurements.
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Order #308643
