VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
Family of Repeater/Retimer and Port
Bypass Circuits for Fibre Channel
VSC7127/VSC7129
Package Thermal Characteristics
The VSC7127/VSC7129 is packaged in a standard plastic quad flatpack, PQFP, with an embedded, but
unexposed thermal heatslug. This package adheres to industry-standard EIAJ footprints for a 10 mm body, 44
lead PQFP. The package construction is as shown in Figure 6. The 44 PQFP with embedded slug has the thermal
properties shown in Figure 6.
Figure 6: Package Cross Section—10 mm package
Copper Heat Spreader
Plastic Molding Compound
Lead
Die
Bond Wire
Table 5: 44 PQFP Thermal Resistance
Symbol
Description
Value
Units
θCA-0
Thermal resistance from case-to-ambient, still air
50
43
39
36
34
oC/W
oC/W
oC/W
oC/W
oC/W
θCA-100
θCA-200
θCA-400
θCA-600
Thermal resistance from case-to-ambient, 100 LFPM air
Thermal resistance from case-to-ambient, 200 LFPM air
Thermal resistance from case-to-ambient, 400 LFPM air
Thermal resistance from case-to-ambient, 600 LFPM air
o
The VSC7127/VSC7129 is designed to operate with a case temperature up to 95 C. The user must guaran-
tee that the case temperature specification is not violated. With the thermal resistances shown in Table 5, the
o
o
o
10mm PQFP can operate in still air ambient temperatures of 50 C [50 C = 95 C - 0.9W * 50]. If the ambient air
temperature exceeds these limits, some form of cooling through a heatsink or an increase in airflow must be pro-
vided.
Moisture Sensitivity Level
This device is rated at a Moisture Sensitivity Level 3 rating with maximum floor life of 168 hours at 30ºC,
60% relative humidity. Please refer to Application Note AN-20 for appropriate handling procedures.
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
G52298-0, Rev 4.3
05/01/01
Page 11
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
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