Intel
®
Pentium
®
III Processor in the FC-PGA2 Package Thermal Design Guidelines
R
8
249660-001
1.3.
Definition of Terms
•
T
LA
- 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. (See Section 7.3: Local-ambient Temperature Measurement Guidelines)
•
T
AMBIENT-OEM
- the target worst-case ambient temperature at a given
external
system location as
defined by the system designer (OEM).
•
T
AMBIENT-EXTERNAL
- the measured ambient temperature at the OEM defined external system location.
•
T
AMBIENT-MAX
- the target worst-case local-ambient temperature. It is determined by placing the
system in maximum external temperature conditions and measuring the ambient temperature locally
surrounding the processor. Under these conditions, T
LA
= T
AMBIENT-MAX
.
•
T
CASE-MAX
- the maximum allowed case temperature of the processor, as specified in the processor
datasheet.
•
T
CASE
- the measured case temperature of the processor.
•
TIM - Thermal Interface Material. The thermally conductive compound between the heatsink and
the processor case. This material fills the air gaps and voids, and enhances the spreading of the heat
from the case to the heatsink.
• θ
TIM
- the thermal resistance of the thermal interface material. Also referred to as
θ
CS
(case to sink
thermal resistance).
• θ
CA
- the thermal resistance between the processor’s case and the ambient air. This is defined and
controlled by the system thermal solution.
•
P
MAX
- the maximum processor power, as specified in the processor’s datasheet.
•
PGA370 Socket - a through-hole mount Zero Insertion Force (ZIF) socket designed to accept the
Intel
®
Pentium
®
III
processor in the FC-PGA2 package.
•
FC-PGA2 package - the Flip Chip Pin Grid Array processor package with an integrated heat
spreader (IHS).
•
ACPI - Advanced Configuration and Power Interface (See
http://www.teleport.com/~acpi/
)
•
Bypass - the area between a passive heatsink or air pass-through and any object that can act to form
a duct. For this example it can be expressed as a dimension away from the outside dimension of the
fins to the nearest surface.
•
TDP - Thermal Design Power. The processor thermal power specification in the processor
datasheet. OEMs must design their processor thermal solutions to meet the TDP as listed in the
respective datasheets.
(Also known as Thermal Design Point.)
•
Intel
®
Pentium
®
III
processor in the FC-PGA2 package - any Pentium
®
III
processor with CPUID
06Bxh, as well as the higher frequencies of Intel
®
Pentium
®
III
processors with CPUID 068xh (see
the
Pentium
®
III
Processor for the PGA370 Socket Datasheet
for further details).
