Specifications

Embedded Thermal Solutions
88 Thermal/Mechanical Design Guide
Detailed drawings for the ATCA reference heatsink can be found in Section E.3.
Table E-1 above specifies Ψ
CA
and pressure drop targets and Figure E-1 below shows
Ψ
CA
and pressure drop for the ATCA heatsink versus the airflow provided. Best-fit
equations are provided to prevent errors associated with reading the graph.
Other LGA1366 compatible thermal solutions may work with the same retention.
E.2 Thermal Design Guidelines
E.2.1 NEBS Thermal Profile
Processors that offer a NEBS compliant thermal profile are specified in the Intel®
Xeon® Processor 5500 Series Datasheet, Volume 1.
NEBS thermal profiles help relieve thermal constraints for Short-Term NEBS conditions.
To help reliability, processors must meet the nominal thermal profile under standard
operating conditions and can only rise up to the Short-Term spec for NEBS excursions
(see Figure E-2). The definition of Short-Term time is clearly defined for NEBS Level 3
conditions but the key is that it cannot be longer than 360 hours per year.
Figure E-1. ATCA Heatsink Performance Curves
0
0.4
0.8
1.2
1.6
2
0
0.5
1
1.5
2
2.5
0 5 10 15 20 25 30 35
ΔP, inch w ater
Ψca, C/W
CFM Through Fins
ΔP = 1.3e-04CFM2 +1.1e-02CFM
Mean Ψ
ca
= 0.337 + 1.625 CFM
-0.939