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Rev. PrA
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Page 44 of 54
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September 2004
ADSP-21365/6
Preliminary Technical Data
THERMAL CHARACTERISTICS
The ADSP-21365/6 processor is rated for performance to a
maximum junction temperature of 125°C.
Table 39
through
Table 42
airflow measurements comply with
JEDEC standards JESD51-2 and JESD51-6 and the junction-to-
board measurement complies with JESD51-8. Test board and
thermal via design comply with JEDEC standards JESD51-9
(Mini-BGA) and JESD51-5 (Integrated Heatsink LQFP). The
junction-to-case measurement complies with MIL- STD-883.
All measurements use a 2S2P JEDEC test board.
Industrial applications using the Mini-BGA package require
thermal vias, to an embedded ground plane, in the PCB. Refer
to JEDEC Standard JESD51-9 for printed circuit board thermal
ball land and thermal via design information. Industrial applica-
tions using the LQFP package require thermal trace squares and
thermal vias, to an embedded ground plane, in the PCB. The
bottom side heat slug must be soldered to the thermal trace
squares. 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
CASE
= Case temperature (
°
C) measured at the top center of
the package
Ψ
JT
= Junction-to-Top (of package) characterization parameter
is the Typical value from
Table 39
and
Table 41
.
P
D
= Power dissipation (see EE Note #TBD)
Values of
θ
JA
are provided for package comparison and PCB
design considerations.
θ
JA
can be used for a first order approxi-
mation of T
J
by the equation:
where:
T
A
= Ambient Temperature
°
C
Values of
θ
JC
are provided for package comparison and PCB
design considerations when an external heatsink is required.
Values of
θ
JB
are provided for package comparison and PCB
design considerations. Note that the thermal characteristics val-
ues provided in
Table 39
through
Table 42
are modeled values.
Figure 41. Typical Output Delay or Hold vs. Load Capacitance
(at Ambient Temperature)
LOAD CAPACITANCE (pF)
0
200
50
100
150
10
8
O
-4
6
0
4
2
-2
Y = 0.0488X - 1.5923
T
J
T
CASE
Ψ
JT
P
D
×
(
)
+
=
Table 39. Thermal Characteristics for 136 Ball Mini-BGA
(No thermal vias in PCB)
Parameter
θ
JA
θ
JMA
θ
JMA
θ
JC
Ψ
JT
Ψ
JMT
Ψ
JMT
Condition
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
Typical
25.20
21.70
20.80
5.00
0.140
0.330
0.410
Unit
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
Table 40. Thermal Characteristics for 136 Ball Mini-BGA
(Thermal vias in PCB)
Parameter
θ
JA
θ
JMA
θ
JMA
θ
JC
Ψ
JT
Ψ
JMT
Ψ
JMT
Condition
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
Typical
22.50
19.30
18.40
5.00
0.130
0.300
0.360
Unit
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
Table 41. Thermal Characteristics for 144-Lead Integrated
Heatsink (INT–HS) LQFP (With heat slug not soldered to
PCB)
Parameter
θ
JA
θ
JMA
θ
JMA
θ
JC
Ψ
JT
Ψ
JMT
Ψ
JMT
Condition
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
Typical
26.08
24.59
23.77
6.83
0.236
0.427
0.441
Unit
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
Airflow = 0 m/s
Airflow = 1 m/s
Airflow = 2 m/s
T
J
T
A
θ
JA
P
D
×
(
)
+
=