mpc8641 Freescale Semiconductor, Inc, mpc8641 Datasheet - Page 113

• Manufacturer Part Number: mpc8641
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

The following section provides a heat sink selection example using one of the commercially available heat
sinks.
19.2.3 Heat Sink Selection Example
For preliminary heat sink sizing, the die-junction temperature can be expressed as follows:
where:
During operation, the die-junction temperatures (T
Table
and the air temperature rise within the electronic cabinet. An electronic cabinet inlet-air temperature (T
may range from 30 to 40 C. The air temperature rise within a cabinet (T
10 C. The thermal resistance of the thermal interface material (R
Freescale Semiconductor
T
j
= T
2. The temperature of air cooling the component greatly depends on the ambient inlet air temperature
i
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Chomerics, Inc.
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Thermagon Inc.
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Internet: www.thermagon.com
T
T
T
R
R
R
P
+ T
i
r
d
j
θJC
θint
θsa
is the die-junction temperature
is the inlet cabinet ambient temperature
is the air temperature rise within the computer cabinet
is the power dissipated by the device
r
is the heat sink base-to-ambient thermal resistance
+ (R
is the junction-to-case thermal resistance
is the adhesive or interface material thermal resistance
MPC8641 and MPC8641D Integrated Host Processor Hardware Specifications, Rev. 2
θJC
+ R
th
St.
θint
+ R
θsa
) × P
d
j
) should be maintained less than the value specified in
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θint
) is typically about 0.2 C/W. For
r
) may be in the range of 5 to
Thermal
113
i
)