Kontron AT8242 User Manual
Page 100
Thermal Considerations
84
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This section provides guidelines on how to use the data presented in the Operating Limits graph. The three
horizontal lines represent the three key temperatures of ATCA specification, which are 25, 40 and 55°C.
Additionally, four zones are shown. They correspond to the CP-TA shelf class. This method gives a quick way
to tell if the product can operate within the cooling limits of each CP-TA shelf class. To determine which shelf
class provides the product with sufficient cooling, the Product Operating Curve shall be above the class line
within the 25°C to 55°C temperature range.
In the example shown here, the product needs at the minimum a Class B.4 shelf for ambient temperatures
below 40°C. For ambient temperatures above 44°C, even the Class B.4 shelf does not provide sufficient
cooling to maintain the product’s components within their maximum temperature limits.
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
0
100
200
300
400
500
600
700
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
0
5
10
15
20
25
30
35
40
45
50
55
60
FLOW (LFM)
MA
X. INLET
TEMP
. (°C)
FLOW (CFM)
OPERATING LIMITS GRAPH
CPU
CLASS B.1
CLASS B.2
CLASS B.3 CLASS B.4