mpc8544e Freescale Semiconductor, Inc, mpc8544e Datasheet - Page 103

• Manufacturer Part Number: mpc8544e
• Description: Mpc8544e Powerquicc Iii Integrated Processor
• Manufacturer: Freescale Semiconductor, Inc

20.3.3
The following section provides a heat sink selection example using one of the commercially available heat
sinks.
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 (θ
of 30°C, a T
expression for T
The heat sink-to-ambient thermal resistance (θ
#2328B is shown in
Assuming an air velocity of 1 m/s, we have an effective θ
resulting in a die-junction temperature of approximately 66, which is well within the maximum operating
temperature of the component.
Freescale Semiconductor
2. The temperature of air cooling the component greatly depends on the ambient inlet air temperature
Chanhassen, MN 55317
Internet: www.bergquistcompany.com
Thermagon Inc. 888-246-9050
4707 Detroit Ave.
Cleveland, OH 44102
Internet: www.thermagon.com
T
T
T
θ
θ
θ
P
JC
INT
SA
D
J
I
R
is the die-junction temperature
is the inlet cabinet ambient temperature
is the power dissipated by the device
is the air temperature rise within the computer cabinet
is the junction-to-case thermal resistance
is the heat sink base-to-ambient thermal resistance
Heat Sink Selection Examples
R
is the adhesive or interface material thermal resistance
T
of 5°C, a FC-PBGA package θ
Die-junction temperature: T
T
J
J
J
MPC8544E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 4
= T
= 30° + 5°C + (0.1°C/W + 1.0°C/W + 5°C/W) × 5
is obtained:
Figure
I
+ T
R
+ (θ
64.
JC
Preliminary—Subject to Change Without Notice
+ θ
INT
Freescale Confidential Proprietary
+ θ
J
= 30°C + 5°C + (0.1°C/W + 1.0°C/W + θ
SA
JC
SA
) × P
= 0.1, and a power consumption (P
) versus airflow velocity for a Thermalloy heat sink
J
) should be maintained within the range specified in
D
SA+
of about 5°C/W, thus
INT
) may be about 1°C/W. Assuming a T
R
) may be in the range of 5° to
D
) of 5, the following
SA
) × P
D
Thermal
103
I
)
I