MPC8533E_10 FREESCALE [Freescale Semiconductor, Inc], MPC8533E_10 Datasheet - Page 96

• Manufacturer Part Number: MPC8533E_10
• Description: Integrated Processor Hardware Specifications
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Thermal
Figure 58
printed-circuit board.
The heat sink removes most of the heat from the device. Heat generated on the active side of the chip is
conducted through the silicon and through the heat sink attach material (or thermal interface material), and
finally to the heat sink. The junction-to-case thermal resistance is low enough that the heat sink attach
material and heat sink thermal resistance are the dominant terms.
20.3.2
A thermal interface material is required at the package-to-heat sink interface to minimize the thermal
contact resistance. For those applications where the heat sink is attached by spring clip mechanism,
Figure 59
graphite/oil, floroether oil), a bare joint, and a joint with thermal grease as a function of contact pressure.
As shown, the performance of these thermal interface materials improves with increasing contact pressure.
The use of thermal grease significantly reduces the interface thermal resistance. The bare joint results in a
thermal resistance approximately six times greater than the thermal grease joint.
96
depicts the primary heat transfer path for a package with an attached heat sink mounted to a
shows the thermal performance of three thin-sheet thermal-interface materials (silicone,
Thermal Interface Materials
(Note the internal versus external package resistance.)
External Resistance
External Resistance
MPC8533E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 4
Internal Resistance
Figure 58. Package with Heat Sink Mounted to a Printed-Circuit Board
Printed-Circuit Board
Heat Sink
Radiation
Radiation
Convection
Convection
Thermal Interface Material
Die/Package
Die Junction
Package/Leads
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