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VSC8121QI 参数 Datasheet PDF下载

VSC8121QI图片预览
型号: VSC8121QI
PDF下载: 下载PDF文件 查看货源
内容描述: 2.488GHz SONET / SDH时钟发生器 [2.488GHz SONET/SDH Clock Generator]
分类和应用: 时钟发生器
文件页数/大小: 18 页 / 178 K
品牌: VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
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VITESSE  
SEMICONDUCTOR CORPORATION  
Data Sheet  
2.488GHz SONET/SDH  
Clock Generator  
VSC8121  
Thermal Considerations  
This package has been enhanced with a copper heat slug to provide a low thermal resistance path from the  
die to the exposed surface of the heat spreader. The thermal resistance is shown in the Table 7.  
Table 7: Thermal Resistance  
Symbol  
Description  
Thermal resistance from junction-to-case.  
oC/W  
θJC  
2.0  
Thermal resistance from case-to-ambient with no airflow, including conduction through  
the leads.  
θCA  
35.0  
Thermal Resistance With Airflow  
Shown in Table 8 is the thermal resistance with airflow. This thermal resistance value reflects all the thermal  
paths including through the leads in an environment where the leads are exposed. The temperature difference  
between the ambient airflow temperature and the case temperature should be the worst-case power of the device  
multiplied by the thermal resistance.  
Table 8: Thermal Resistance With Airflow  
Airflow  
θ
CA (oC/W)  
100 lfpm  
200 lfpm  
400 lfpm  
600 lfpm  
28  
25  
21  
18  
Maximum Ambient Temperature Without Heatsink  
The worst case ambient temperature without use of a heatsink is given by the equation:  
T
= T  
- P θ  
(MAX) CA  
A(MAX)  
C(MAX)  
where:  
θ
T
T
P
= Theta case to ambient at appropriate airflow  
= Ambient Air temperature  
= Case temperature (85oC for VSC8121)  
= Power (0.7W for VSC8121)  
CA  
A(MAX)  
C(MAX)  
(MAX)  
Table 9: Maximum Ambient Air Temperature Without Heatsink  
Airflow  
TA(MAX) oC  
None  
60  
65  
68  
70  
72  
100 lfpm  
200 lfpm  
400 lfpm  
600 lfpm  
Note that ambient air temperature varies throughout the system based on the positioning and magnitude of  
heat sources and the direction of air flow.  
© VITESSE SEMICONDUCTOR CORPORATION 741 Calle Plano Camarillo, CA 93012  
Tel: (800) VITESSE FAX: (805) 987-5896 Email: prodinfo@vitesse.com  
Internet: www.vitesse.com  
Page 12  
G52163-0, Rev 4.2  
04/16/01