MPC8270 MOTOROLA [Motorola, Inc], MPC8270 Datasheet - Page 12

• Manufacturer Part Number: MPC8270
• Description: PowerQUICC II Family Hardware Specifications
• Manufacturer: MOTOROLA [Motorola, Inc]

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2
3
4
4
Table 6 describes thermal characteristics for both the packages. See Table 2 for information about a given
device’s package. For the discussions sections 4.1 and 4.2, P
power dissipation of the I/O drivers.
4.1
An estimation of the chip junction temperature, T
where:
The junction-to-ambient thermal resistance is an industry standard value that provides a quick and easy
estimation of thermal performance. However, the answer is only an estimate; test cases have demonstrated
that errors of a factor of two (in the quantity T
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Junction to ambient—
single-layer board
Junction to ambient—
four-layer board
Junction to board
Junction to case
Junction-to-package top
Thermal resistance between the die and the case top surface as measured by the cold plate method (MIL SPEC-883
Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is
Thermal characterization parameter indicating the temperature difference between package top and the junction
Assumes no thermal vias
measured on the top surface of the board near the package.
Method 1012.1).
temperature per JEDEC JESD51-2. When Greek letters are not available, the thermal characterization parameter is
written as Psi-JT.
Characteristic
T
R
P
A
D
θJA
Thermal Characteristics
= ambient temperature (ºC)
= power dissipation in package
Estimation with Junction-to-Ambient Thermal
Resistance
= package junction-to-ambient thermal resistance (ºC/W)
T
3
2
J
1
= T
MPC8280 PowerQUICC II™ Family Hardware Specifications
4
A
+ (R
Symbol
R
R
R
R
Ψ
θJA
θJA
θJA
θJB
θJC
JT
× P
Table 6. Thermal Characteristics
D
)
480 TBGA
16
11
12
6
2
2
J
9
– T
J
, in °C can be obtained from the following equation:
A
) are possible.
Value
516 PBGA
D
27
21
19
16
11
8
2
= (V
DD
× I
DD
°C/W
°C/W
°C/W
°C/W
°C/W
Unit
) + PI/O, where PI/O is the
Natural convection
Natural convection
Air Flow
1 m/s
1 m/s
MOTOROLA
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