vsc8169 Vitesse Semiconductor Corp, vsc8169 Datasheet - Page 17

• Manufacturer Part Number: vsc8169
• Description: Oc-48 Fec 16 1 Sonet/sdh Mux With Clock Generator
• Manufacturer: Vitesse Semiconductor Corp

G52230-0, Rev 3.6
01/02/01
Preliminary Data Sheet
VSC8169
Thermal Considerations
die to the exposed surface of the heat spreader. The thermal resistance is shown in the Table 4.
Table 4: Thermal Resistance
Thermal Resistance with Airflow
thermal paths including through the leads in an environment where the leads are exposed. The temperature dif-
ference between the ambient airflow temperature and the case temperature should be the worst case power of
the device multiplied by the thermal resistance.
Table 5: Thermal Resistance with Airflow
Maximum Ambient Temperature without Heatsink
Symbol
JC
CA
The worst-case ambient temperature without use of a heatsink is given by the equation:
where:
P
This package has been enhanced with a copper heat slug to provide a low thermal resistance path from the
Shown in the Table 5 is the thermal resistance with airflow. This thermal resistance value reflects all the
CA
A(MAX)
(MAX)
C(MAX)
100 lfpm
200 lfpm
400 lfpm
600 lfpm
Airflow
Theta case-to-ambient at appropriate airflow
Ambient air temperature
Case temperature (85
Power (1.7 W for VSC8169)
Thermal resistance from junction-to-case.
Thermal resistance from case-to-ambient with no airflow, including conduction
through the leads.
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]
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VITESSE
SEMICONDUCTOR CORPORATION
14.5
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C/W
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A MAX
C for VSC8169)
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Internet: www.vitesse.com
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Description
T
C MAX
–
P
MAX
CA
OC-48 (FEC) 16:1 SONET/SDH
MUX with Clock Generator
1.34
25.0
C/W
Page 17