2 reference documents, 3 definition of terms, Reference documents – Intel CELERON 200 User Manual
Page 9: Definition of terms

Introduction
Thermal and Mechanical Design Guidelines
9
1.2
Reference Documents
Material and concepts available in the following documents may be beneficial when
reading this document.
Document Document
No./Location
Intel
®
Celeron
®
Processor 200 Sequence Datasheet
Power Supply Design Guide for Desktop Platform Form Factors (Rev
1.1)
ATX Thermal Design Suggestions
microATX Thermal Design Suggestions
Balanced Technology Extended (BTX) System Design Guide
Thermally Advantaged Chassis version 1.1
o/chassis/
1.3
Definition of Terms
Term Description
T
A
The measured ambient temperature locally surrounding the processor. The
ambient temperature should be measured just upstream of a passive heatsink or
at the fan inlet for an active heatsink.
T
J
Processor junction temperature.
T
S-TOP
Heatsink temperature measured at vicinity to center on the top surface of
heatsink base.
Ψ
JA
Junction-to-ambient thermal characterization parameter (psi). A measure of
thermal solution performance using total package power. Defined as
(T
J
– T
A
) / Total Package Power.
Note: Heat source must be specified for Ψ measurements.
Ψ
JS
Junction-to-sink thermal characterization parameter. A measure of thermal
interface material performance using total package power. Defined as
(T
J
– T
S
) / Total Package Power.
Note: Heat source must be specified for Ψ measurements.
Ψ
SA
Sink-to-ambient thermal characterization parameter. A measure of heatsink
thermal performance using total package power. Defined as