mpc8641 Freescale Semiconductor, Inc, mpc8641 Datasheet - Page 111

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

Ultimately, the final selection of an appropriate heat sink depends on many factors, such as thermal
performance at a given air velocity, spatial volume, mass, attachment method, assembly, and cost.
19.2.1
For the exposed-die packaging technology described in
resistance paths are as follows:
Figure 60
printed-circuit board.
Heat generated on the active side of the chip is conducted through the silicon, through the heat sink attach
material (or thermal interface material), and finally to the heat sink where it is removed by forced-air
convection.
Because the silicon thermal resistance is quite small, the temperature drop in the silicon may be neglected
for a first-order analysis. Thus the thermal interface material and the heat sink conduction/convective
thermal resistances are the dominant terms.
Freescale Semiconductor
•
•
Tyco Electronics
Chip Coolers™
P.O. Box 3668
Harrisburg, PA 17105-3668
Internet: www.chipcoolers.com
Wakefield Engineering
33 Bridge St.
Pelham, NH 03076
Internet: www.wakefield.com
The die junction-to-case thermal resistance (the case is actually the top of the exposed silicon die)
The die junction-to-board thermal resistance
depicts the primary heat transfer path for a package with an attached heat sink mounted to a
Internal Package Conduction Resistance
MPC8641 and MPC8641D Integrated Host Processor Hardware Specifications, Rev. 2
(Note the internal versus external package resistance.)
Figure 60. C4 Package with Heat Sink Mounted to a Printed-Circuit Board
External Resistance
External Resistance
Internal Resistance
Printed-Circuit Board
Heat Sink
Radiation
Radiation
Table
Convection
Convection
800-522-6752
603-635-5102
71, the intrinsic conduction thermal
Thermal Interface Material
Die/Package
Die Junction
Package/Leads
Thermal
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