Datasheet

ADSP-21367/ADSP-21368/ADSP-21369
Rev. F | Page 53 of 64 | October 2013
THERMAL CHARACTERISTICS
The ADSP-21367/ADSP-21368/ADSP-21369 processors are
rated for performance over the temperature range specified in
Operating Conditions on Page 16.
Table 43 and Table 44 airflow measurements comply with
JEDEC standards JESD51-2 and JESD51-6 and the junction-to-
board measurement complies with JESD51-8. Test board design
complies with JEDEC standards JESD51-9 (BGA_ED) and
JESD51-8 (LQFP_EP). The junction-to-case measurement com-
plies with MIL-STD-883. All measurements use a 2S2P JEDEC
test board.
The LQFP-EP package requires thermal trace squares and ther-
mal vias, to an embedded ground plane, in the PCB. Refer to
JEDEC standard JESD51-5 for more information.
To determine the junction temperature of the device while on
the application PCB, use:
where:
T
J
= junction temperature (C)
T
TOP
= case temperature (C) measured at the top center of the
package

JT
= junction-to-top (of package) characterization parameter is
the typical value from Table 43 and Table 44.
P
D
= power dissipation (see Engineer-to-Engineer Note EE-299)
Values of 
JA
are provided for package comparison and PCB
design considerations. 
JA
can be used for a first-order approxi-
mation of T
J
by the equation:
where:
T
A
= ambient temperature (C)
Values of 
JC
are provided for package comparison and PCB
design considerations when an external heat sink is required.
This is only applicable when a heat sink is used.
Values of 
JB
are provided for package comparison and PCB
design considerations. The thermal characteristics values pro-
vided in Table 43 and Table 44 are modeled values @ 2 W.
Figure 47. Typical Output Delay or Hold vs. Load Capacitance
(at Junction Temperature)
Figure 48. SDCLK Typical Output Delay or Hold vs. Load Capacitance
(at Junction Temperature)
LOAD CAPACITANCE (pF)
0 20050 100 150
10
8
O
U
T
P
U
T
D
E
L
A
Y
O
R
H
O
L
D
(
n
s
)
- 4
6
0
4
2
- 2
y = 0.0488x - 1.5923
LOAD CAPACITANCE
(
p
F
)
6
- 2
0100
2
0
8
4
R
I
S
E
A
N
D
F
A
L
L
T
I
M
E
S
(
n
s
)
20015050
y = 0.0256x - 0.021
Table 43. Thermal Characteristics for 256-Ball BGA_ED
Parameter Condition Typical Unit

JA
Airflow = 0 m/s 12.5 C/W

JMA
Airflow = 1 m/s 10.6 C/W

JMA
Airflow = 2 m/s 9.9 C/W

JC
0.7 C/W

JB
5.3 C/W

JT
Airflow = 0 m/s 0.3 C/W

JMT
Airflow = 1 m/s 0.3 C/W

JMT
Airflow = 2 m/s 0.3 C/W
Table 44. Thermal Characteristics for 208-Lead LQFP EPAD
(With Exposed Pad Soldered to PCB)
Parameter Condition Typical Unit

JA
Airflow = 0 m/s 17.1 C/W

JMA
Airflow = 1 m/s 14.7 C/W

JMA
Airflow = 2 m/s 14.0 C/W

JC
9.6 C/W

JT
Airflow = 0 m/s 0.23 C/W

JMT
Airflow = 1 m/s 0.39 C/W

JMT
Airflow = 2 m/s 0.45 C/W

JB
Airflow = 0 m/s 11.5 C/W

JMB
Airflow = 1 m/s 11.2 C/W

JMB
Airflow = 2 m/s 11.0 C/W
T
J
T
TOP

JT
P
D
 +=
T
J
T
A

JA
P
D
 +=