ADSP-BF561 Datasheet, PDF (45/64 Pages) Analog Devices – Blackfin Embedded Symmetric Multi-Processor

In Table 30 through Table 32, airflow measurements comply
with JEDEC standards JESD51–2 and JESD51–6, and the junc-
tion-to-board measurement complies with JESD51–8. The
junction-to-case measurement complies with MIL-STD-883
(Method 1012.1). All measurements use a 2S2P JEDEC test
board.
Thermal resistance θ_JA in Table 30 through Table 32 is the figure
of merit relating to performance of the package and board in a
convective environment. θ_JMA represents the thermal resistance
under two conditions of airflow. θ_JB represents the heat
extracted from the periphery of the board. Ψ_JT represents the
correlation between T_J and T_CASE. Values of θ_JB are provided for
package comparison and printed circuit board design
considerations.
Table 30. Thermal Characteristics for BC-256-4
(17 mm × 17 mm) Package
Parameter
θ_JA
θ_JMA
θ_JMA
θ_JC
Ψ_JT
Ψ_JT
Ψ_JT
Condition
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Not Applicable
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Typical
18.1
15.9
15.1
3.72
0.11
0.18
0.18
Unit
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
Table 31. Thermal Characteristics for BC-256-1
(12 mm × 12 mm) Package
Parameter
θ_JA
θ_JMA
θ_JMA
θ_JB
θ_JC
Ψ_JT
Ψ_JT
Ψ_JT
Condition
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Not Applicable
Not Applicable
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Typical
25.6
22.4
21.6
18.9
4.85
0.15
n/a
n/a
Unit
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
Table 32. Thermal Characteristics for B-297 Package
Parameter
θ_JA
θ_JMA
θ_JMA
θ_JB
θ_JC
Ψ_JT
Ψ_JT
Ψ_JT
Condition
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Not Applicable
Not Applicable
0 Linear m/s Airflow
1 Linear m/s Airflow
2 Linear m/s Airflow
Typical
20.6
17.8
17.4
16.3
7.15
0.37
n/a
n/a
Unit
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
؇C/W
Rev. C | Page 45 of 64 | December 2007
ADSP-BF561