MPC8347 FREESCALE [Freescale Semiconductor, Inc], MPC8347 Datasheet - Page 95

• Manufacturer Part Number: MPC8347
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

20.2.4
Some application environments require a heat sink to provide the necessary thermal management of the
device. When a heat sink is used, the thermal resistance is expressed as the sum of a junction to case
thermal resistance and a case-to-ambient thermal resistance:
R
change the case to ambient thermal resistance, R
sink, the air flow around the device, the interface material, the mounting arrangement on printed circuit
board, or change the thermal dissipation on the printed circuit board surrounding the device.
The thermal performance of devices with heat sinks has been simulated with a few commercially available
heat sinks. The heat sink choice is determined by the application environment (temperature, air flow,
adjacent component power dissipation) and the physical space available. Because there is not a standard
application environment, a standard heat sink is not required.
Table 66
Freescale Semiconductor
θ
JC
MEI, 75
is device-related and cannot be influenced by the user. The user controls the thermal environment to
and
MEI, 75
MEI, 75
MEI, 75
Heat Sinks and Junction-to-Case Thermal Resistance
×
MPC8347EA PowerQUICC II Pro Integrated Host Processor Hardware Specifications, Rev. 3
Table 67
Heat Sink Assuming Thermal Grease
85
Wakefield, 53
Wakefield, 53
Wakefield, 53
AAVID 30
AAVID 30
AAVID 30
AAVID 31
AAVID 31
AAVID 31
×
×
×
×
12 mm, adjacent board, 40 mm Side bypass
R
where:
85
85
85
Table 66. Heat Sink and Thermal Resistance of MPC8347EA (TBGA)
θ
JA
×
×
×
show heat sink thermal resistance for TBGA and PBGA of the MPC8347EA.
= R
12 no adjacent board, extrusion
12 no adjacent board, extrusion
12 no adjacent board, extrusion
R
R
R
×
×
×
×
×
×
θ
θ
θ
JA
JC
CA
30
30
30
×
×
×
θ
35
35
35
JC
53
53
53
= junction to ambient thermal resistance (°C/W)
= junction to case thermal resistance (°C/W)
= case to ambient thermal resistance (°C/W)
×
×
×
×
×
×
+ R
9.4 mm Pin Fin
9.4 mm Pin Fin
9.4 mm Pin Fin
×
×
×
23 mm Pin Fin
23 mm Pin Fin
23 mm Pin Fin
25 mm Pin Fin
25 mm Pin Fin
25 mm Pin Fin
θ
CA
θ
CA
. For instance, the user can change the size of the heat
Natural Convection
Natural Convection
Natural Convection
Natural Convection
Air Flow
1 m/s
2 m/s
1 m/s
2 m/s
1 m/s
2 m/s
1 m/s
2 m/s
1 m/s
Thermal Resistance
35
×
35 mm TBGA
6.5
5.6
8.4
4.7
5.7
3.5
2.7
6.7
4.1
2.8
3.1
10
4
Thermal
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