VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
2.488Gb/s SONET/SDH
STS-48/STM-16 Section Terminator
VSC8151
Package Thermal Characteristics
The VSC8151 is packaged in an 160 pin, 28mm x 28mm thermally enhanced PQFP (EDQUAD) with an
exposed heatsink. These packages use industry-standard JDEC footprints, but have been enhanced to improve
thermal dissipation. The construction of the packages are as shown in Figure 13. A heat sink may be necessary
depending on the ambient temperature and airflow available in your system. Commercially available heatsinks
are available to improve θca so that the case temperature is kept within the 85C specification.
Figure 17: Package Cross Section
Plastic Molding
Exposed Heat Slug
Insulator
Lead
Die
Wire Bond
Table 19: 160-Pin Enhanced PQFP Thermal Resistance
Symbol
Description
Value
Units
θca-0
θca-1
θca-2
θca-4
Thermal resistance from case to ambient, still air
Thermal resistance from case to ambient, 1 m/sec air
Thermal resistance from case to ambient, 2 m/sec air
Thermal resistance from case to ambient, 3 m/sec air
24
14
11
10
oC/W
oC/W
oC/W
oC/W
G52225-0, Rev. 2.3
8/16/99
VITESSE SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
Page 27
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