MPC8308VMAGDA Freescale Semiconductor, MPC8308VMAGDA Datasheet - Page 76

• Manufacturer Part Number: MPC8308VMAGDA
• Description: Microprocessors - MPU E300 MP PbFr 400
• Manufacturer: Freescale Semiconductor

Specifications of MPC8308VMAGDA

• Rohs: yes
• Processor Series: MPC8308
• Core: e300
• Maximum Clock Frequency: 400 MHz
• Interface Type: I2C, JTAG, UART
• Operating Supply Voltage: 0.95 V to 1.05 V
• Maximum Operating Temperature: 0 C to + 105 C
• Mounting Style: SMD/SMT
• Package / Case: MAPBGA-473

Thermal
appropriate for a tightly packed printed-circuit board. The value obtained on the board with the internal
planes is usually appropriate if the board has low power dissipation and the components are well separated.
Test cases have demonstrated that errors of a factor of two (in the quantity T
22.2.2
The thermal performance of a device cannot be adequately predicted from the junction-to-ambient thermal
resistance. The thermal performance of any component is strongly dependent on the power dissipation of
surrounding components. In addition, the ambient temperature varies widely within the application. For
many natural convection and especially closed box applications, the board temperature at the perimeter
(edge) of the package is approximately the same as the local air temperature near the device. Specifying
the local ambient conditions explicitly as the board temperature provides a more precise description of the
local ambient conditions that determine the temperature of the device.
At a known board temperature, the junction temperature is estimated using the following equation:
where:
When the heat loss from the package case to the air can be ignored, acceptable predictions of junction
temperature can be made. The application board should be similar to the thermal test condition: the
component is soldered to a board with internal planes.
22.2.3
To determine the junction temperature of the device in the application after prototypes are available, the
thermal characterization parameter (
measurement of the temperature at the top center of the package case using the following equation:
where:
The thermal characterization parameter is measured per JESD51-2 specification using a 40 gauge type T
thermocouple epoxied to the top center of the package case. The thermocouple should be positioned so
that the thermocouple junction rests on the package. A small amount of epoxy is placed over the
thermocouple junction and over about 1 mm of wire extending from the junction. The thermocouple wire
is placed flat against the package case to avoid measurement errors caused by cooling effects of the
thermocouple wire.
76
T
T
R
P
T
T

P
J
B
J
T

D
D
JT
JB
= junction temperature (C)
= junction temperature (C)
= thermocouple temperature on top of package (C)
= board temperature at the package perimeter (C)
= power dissipation in the package (W)
= power dissipation in the package (W)
Estimation of Junction Temperature with Junction-to-Board
Thermal Resistance
Experimental Determination of Junction Temperature
= thermal characterization parameter (C/W)
= junction-to-board thermal resistance (C/W) per JESD51–8
T
T
J
J
= T
= T
B
T
MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 3
+ (
+ (R


JT
JB
 P
 P
D
D
)
)

JT
) can be used to determine the junction temperature with a
J
– T
A
) are possible.
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