MC7447AVU733NB Freescale Semiconductor, MC7447AVU733NB Datasheet - Page 47

• Manufacturer Part Number: MC7447AVU733NB
• Description: IC MPU RISC 32BIT 360-BGA
• Manufacturer: Freescale Semiconductor

Specifications of MC7447AVU733NB

• Processor Type: MPC74xx PowerPC 32-Bit
• Speed: 733MHz
• Voltage: 1.1V
• Mounting Type: Surface Mount
• Package / Case: 360-BGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

The following section provides a heat sink selection example using one of the commercially available heat
sinks.
9.8.3
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 (R
example, assuming a T
consumption (P
Die-junction temperature: T
For this example, a R
the maximum value of
Though the die-junction-to-ambient and the heat-sink-to-ambient thermal resistances are a common
figure-of-merit used for comparing the thermal performance of various microelectronic packaging
technologies, one should exercise caution when only using this metric in determining thermal management
because no single parameter can adequately describe three-dimensional heat flow. The final die-junction
operating temperature is not only a function of the component-level thermal resistance, but the
system-level design and its operating conditions. In addition to the component's power consumption, a
number of factors affect the final operating die-junction temperature—airflow, board population (local
Freescale Semiconductor
4. The temperature of air cooling the component greatly depends on the ambient inlet air temperature
Shin-Etsu MicroSi, Inc.
10028 S. 51st St.
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Internet: www.microsi.com
Thermagon Inc.
4707 Detroit Ave.
Cleveland, OH 44102
Internet: www.thermagon.com
T
T
T
R
R
R
P
i
r
d
j
θJC
θint
θsa
is the die-junction temperature
is the inlet cabinet ambient temperature
is the air temperature rise within the computer cabinet
is the power dissipated by the device
Heat Sink Selection Example
is the heat sink base-to-ambient thermal resistance
is the junction-to-case thermal resistance
is the adhesive or interface material thermal resistance
T
d
) of 18.7 W, the following expression for T
j
= T
θsa
i
i
+ T
Table
value of 2.1°C/W or less is required to maintain the die junction temperature below
MPC7447A RISC Microprocessor Hardware Specifications, Rev. 5
of 30°C, a T
r
+ (R
4.
j
= 30°C + 5°C + (0.1°C/W + 1.5°C/W + R
θJC
+ R
r
of 5°C, an HCTE package R
θint
+ R
θsa
) × P
j
) should be maintained less than the value specified in
d
j
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is obtained:
θint
θJC
) is typically about 1.5°C/W. For
= 0.1, and a typical power
θsa
r
) may be in the range of 5° to
) × 18.7 W
System Design Information
i
47
)