PCX745BVZFU350LE Atmel, PCX745BVZFU350LE Datasheet - Page 21

• Manufacturer Part Number: PCX745BVZFU350LE
• Description: IC MPU 32BIT 350MHZ 255PBGA
• Manufacturer: Atmel

Specifications of PCX745BVZFU350LE

• Processor Type: PowerPC 32-Bit RISC
• Speed: 350MHz
• Voltage: 2V
• Mounting Type: Surface Mount
• Package / Case: 255-PBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

6.1.5
2138G–HIREL–05/06
Heat Sink Selection Example
For preliminary heat sink sizing, the die-junction temperature can be expressed as follows:
Where
During operation the die-junction temperatures (T
specified in
cooling the component greatly depends upon the ambient inlet air temperature and the air tem-
perature rise within the electronic cabinet. An electronic cabinet inlet-air temperature (T
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
Assuming a T
of 5.0 watts, the following expression for T
Die-junction temperature: T
For a Thermalloy heat sink #2328B, the heat sink-to-ambient thermal resistance (θ
flow velocity is shown in
Figure 6-4.
T
T
T
θ
θ
θ
P
:
T
JC
INT
SA
J
A
R
D
J
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
= T
is the junction-to-case thermal resistance
is the heat sink base-to-ambient thermal resistance
is the adhesive or interface material thermal resistance
“Recommended Operating Conditions
A
A
+ T
Thermalloy #2328B Heat Sink-to-Ambient Thermal Resistance Versus Airflow
Velocity
8
7
6
5
4
3
2
1
of 30°C, a T
0
R
+ (θ
JC
Figure
0.5
+ θ
J
R of 5
= 30°C + 5°C + (0.03°C/W + 1.0°C/W + θ
INT
6-4.
o
+ θ
C, a CBGA package θ
SA
1
Approach Air Velocity (m/s)
) × P
J
D
is obtained:
1.5
Thermalloy #2328B Pin±fin Heat Sink
J
(1)
) should be maintained less than the value
” on page
(25 x28 x 15 mm)
2
JC
= 0.03, and a power consumption (P
2.5
16. The temperature of the air
R
INT
) may be in the range of 5 to
) is typically about 1°C/W.
sa
) × 5.0 W
3
PC755/745
3.5
sa
) versus air-
A
) may
21
D
)