cx28331 Mindspeed Technologies, cx28331 Datasheet - Page 57

• Manufacturer Part Number: cx28331
• Description: Single/dual/triple E3/ds3/sts-1line Interface Unit
• Manufacturer: Mindspeed Technologies

CX28331/CX28332/CX28333 (-1x)
Single/Dual/Triple E3/DS3/STS-1 Line Interface Unit
B.2.5 Package Thermal Performance
Table B-4. Specification for Delco Thermal Test Chips
Figure B-6. Package Thermal Resistance as a Function of Airflow Velocity for a 48-ETQFP Package
28333-DSH-001-A
Dimensions
Thickness
Thermal Resistance
B.2.5.1 Calculation
B.2.5.2 Package
Guidelines
80
70
60
50
40
30
20
10
0
3.81 mm x 3.81 mm
0.33 mm
0
50
Maximum junction temperature can be calculated as:
Where:
Delco thermal test chips are used to estimate package thermal performance.
Table B-4
Figure B-6
for a 48-pin ETQFP package using two different test boards, specified in
Tables B-2
B-8
Table B-5
100
T
T
T
P
illustrates the similar information for a 64- and 80-pin ETQFP package.
a
j
j
ja
Mindspeed Proprietary and Confidential
= P x
150
= Maximum Junction Temperature (C)
= Ambient Temperature (C)
= Package Total Power Dissipation Value (W)
Mindspeed Technologies
= Equivalent Package Thermal Resistance (C/W)
Air Flow Velocity (LFM)
lists thermal die specifications.
lists the test condition for each package type.
illustrates package thermal resistance as a function of airflow velocity
and B-3, and a prediction for a six-layer PCB design.
200
ja
+ T
6.35 mm x 6.35 mm
0.45 mm
a
250
300
Two Layer PCB
Four Layer PCB
Six Layer PCB
Appendix B: Exposed Thin Quad Flat (ETQFP) Pack
350
400
™
7.8 mm x 7.8 mm
0.5 mm
450
B.2 Package Thermal Characterization
500
100998_031
Figures B-7
and
B-7