Datasheet

ADSP-BF531/ADSP-BF532/ADSP-BF533
Rev. I | Page 49 of 64 | August 2013
THERMAL CHARACTERISTICS
To determine the junction temperature on the application
printed circuit board, use:
where:
T
J
= Junction temperature (°C).
T
CASE
= Case temperature (°C) measured by customer at top
center of package.

JT
= From Table 38 through Table 40.
P
D
= Power dissipation (see the power dissipation discussion
and the tables on 23 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 (°C).
In Table 38 through Table 40, 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 
JA
in Table 38 through Table 40 is the figure
of merit relating to performance of the package and board in a
convective environment. 
JMA
represents the thermal resistance
under two conditions of airflow. 
JT
represents the correlation
between T
J
and T
CASE
.
T
J
T
CASE

JT
P
D
+=
T
J
T
A

JA
P
D
+=
Table 38. Thermal Characteristics for BC-160 Package
Parameter Condition Typical Unit

JA
0 Linear m/s Airflow 27.1 °C/W

JMA
1 Linear m/s Airflow 23.85 °C/W

JMA
2 Linear m/s Airflow 22.7 °C/W

JC
Not Applicable 7.26 °C/W

JT
0 Linear m/s Airflow 0.14 °C/W

JT
1 Linear m/s Airflow 0.26 °C/W

JT
2 Linear m/s Airflow 0.35 °C/W
Table 39. Thermal Characteristics for ST-176-1 Package
Parameter Condition Typical Unit

JA
0 Linear m/s Airflow 34.9 °C/W

JMA
1 Linear m/s Airflow 33.0 °C/W

JMA
2 Linear m/s Airflow 32.0 °C/W

JT
0 Linear m/s Airflow 0.50 °C/W

JT
1 Linear m/s Airflow 0.75 °C/W

JT
2 Linear m/s Airflow 1.00 °C/W
Table 40. Thermal Characteristics for B-169 Package
Parameter Condition Typical Unit

JA
0 Linear m/s Airflow 22.8 °C/W

JMA
1 Linear m/s Airflow 20.3 °C/W

JMA
2 Linear m/s Airflow 19.3 °C/W

JC
Not Applicable 10.39 °C/W

JT
0 Linear m/s Airflow 0.59 °C/W

JT
1 Linear m/s Airflow 0.88 °C/W

JT
2 Linear m/s Airflow 1.37 °C/W