Datasheet

ADSP-BF538/ADSP-BF538F
Rev. E | Page 53 of 60 | November 2013
THERMAL CHARACTERISTICS
To determine the junction temperature on the application
printed circuit board use
where:
T
J
= junction temperature (ⴗC)
T
CASE
= case temperature (ⴗC) measured by customer at top cen-
ter of package.

JT
= from Table 41 or Table 42
P
D
= power dissipation (see Electrical Characteristics on Page 25
for the method to calculate P
D
)
Values of 
JA
are provided for package comparison and printed
circuit board design considerations. 
JA
can be used for a first
order approximation of T
J
by the equation
where:
T
A
= ambient temperature (ⴗC)
Values of 
JC
are provided for package comparison and printed
circuit board design considerations when an external heatsink is
required.
Values of 
JB
are provided for package comparison and printed
circuit board design considerations.
In Table 41 and Table 42, airflow measurements comply with
JEDEC standards JESD51-2 and JESD51-6, and the junction-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.
T
J
T
CASE

JT
P
D
+=
T
J
T
A

JA
P
D
+=
Table 41. Thermal Characteristics BC-316-2 without Flash
Parameter Condition Typical Unit

JA
0 Linear m/s Airflow 25.4 ⴗC/W

JMA
1 Linear m/s Airflow 22.8 ⴗC/W

JMA
2 Linear m/s Airflow 22.0 ⴗC/W

JC
6.7 ⴗC/W

JT
0 Linear m/s Airflow 0.18 ⴗC/W

JT
1 Linear m/s Airflow 0.38 ⴗC/W

JT
2 Linear m/s Airflow 0.40 ⴗC/W
Table 42. Thermal Characteristics BC-316-2 with Flash
Parameter Condition Typical Unit

JA
0 Linear m/s Airflow 24.3 ⴗC/W

JMA
1 Linear m/s Airflow 21.8 ⴗC/W

JMA
2 Linear m/s Airflow 21.0 ⴗC/W

JC
6.3 ⴗC/W

JT
0 Linear m/s Airflow 0.17 ⴗC/W

JT
1 Linear m/s Airflow 0.36 ⴗC/W

JT
2 Linear m/s Airflow 0.38 ⴗC/W