mpc8343e Freescale Semiconductor, Inc, mpc8343e Datasheet - Page 72

• Manufacturer Part Number: mpc8343e
• Description: Mpc8343e Powerquicc
• Manufacturer: Freescale Semiconductor, Inc

Thermal
Interface material vendors include the following:
20.3
When heat sinks are attached, an interface material is required, preferably thermal grease and a spring clip.
The spring clip should connect to the printed-circuit board, either to the board itself, to hooks soldered to
the board, or to a plastic stiffener. Avoid attachment forces that can lift the edge of the package or peel the
package from the board. Such peeling forces reduce the solder joint lifetime of the package. The
recommended maximum force on the top of the package is 10 lb force (4.5 kg force). Any adhesive
attachment should attach to painted or plastic surfaces, and its performance should be verified under the
application requirements.
20.3.1
When a heat sink is used, the junction temperature is determined from a thermocouple inserted at the
interface between the case of the package and the interface material. A clearance slot or hole is normally
required in the heat sink. Minimize the size of the clearance to minimize the change in thermal
performance caused by removing part of the thermal interface to the heat sink. Because of the experimental
difficulties with this technique, many engineers measure the heat sink temperature and then back calculate
the case temperature using a separate measurement of the thermal resistance of the interface. From this
case temperature, the junction temperature is determined from the junction-to-case thermal resistance.
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Chomerics, Inc.
77 Dragon Ct.
Woburn, MA 01801
Internet: www.chomerics.com
Dow-Corning Corporation
Dow-Corning Electronic Materials
P.O. Box 994
Midland, MI 48686-0997
Internet: www.dowcorning.com
Shin-Etsu MicroSi, Inc.
10028 S. 51st St.
Phoenix, AZ 85044
Internet: www.microsi.com
The Bergquist Company
18930 West 78th St.
Chanhassen, MN 55317
Internet: www.bergquistcompany.com
Heat Sink Attachment
MPC8343E PowerQUICC™ II Pro Integrated Host Processor Hardware Specifications, Rev. 11
Experimental Determination of the Junction Temperature with a
Heat Sink
T
J
= T
C
+ (R
θ
JC
× P
D
)
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