MPC870CZT66 Freescale Semiconductor, MPC870CZT66 Datasheet - Page 13
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MPC870CZT66
Manufacturer Part Number
MPC870CZT66
Description
IC MPU POWERQUICC 66MHZ 256PBGA
Manufacturer
Freescale Semiconductor
Datasheet
1.MPC870VR80.pdf
(84 pages)
Specifications of MPC870CZT66
Processor Type
MPC8xx PowerQUICC 32-Bit
Speed
66MHz
Voltage
3.3V
Mounting Type
Surface Mount
Package / Case
256-PBGA
Family Name
MPC8xx
Device Core
PowerQUICC
Device Core Size
32b
Frequency (max)
66MHz
Instruction Set Architecture
RISC
Supply Voltage 1 (typ)
1.8V
Operating Supply Voltage (max)
1.9V
Operating Supply Voltage (min)
1.7V
Operating Temp Range
-40C to 100C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
256
Package Type
BGA
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Features
-
Lead Free Status / Rohs Status
Not Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
MPC870CZT66
Manufacturer:
MOT
Quantity:
12 388
Company:
Part Number:
MPC870CZT66
Manufacturer:
Freescale Semiconductor
Quantity:
10 000
7.2
Historically, thermal resistance has frequently been expressed as the sum of a junction-to-case thermal
resistance and a case-to-ambient thermal resistance:
where:
R
affect the case-to-ambient thermal resistance, R
the device, add a heat sink, change the mounting arrangement on the printed-circuit board, or change the
thermal dissipation on the printed-circuit board surrounding the device. This thermal model is most useful
for ceramic packages with heat sinks where some 90% of the heat flows through the case and the heat sink
to the ambient environment. For most packages, a better model is required.
7.3
A simple package thermal model that has demonstrated reasonable accuracy (about 20%) is a two-resistor
model consisting of a junction-to-board and a junction-to-case thermal resistance. The junction-to-case
thermal resistance covers the situation where a heat sink is used or where a substantial amount of heat is
dissipated from the top of the package. The junction-to-board thermal resistance describes the thermal
performance when most of the heat is conducted to the printed-circuit board. It has been observed that the
thermal performance of most plastic packages and especially PBGA packages is strongly dependent on the
board temperature. If the board temperature is known, an estimate of the junction temperature in the
environment can be made using the following equation:
where:
If the board temperature is known and the heat loss from the package case to the air can be ignored,
acceptable predictions of junction temperature can be made. For this method to work, the board and board
mounting must be similar to the test board used to determine the junction-to-board thermal resistance,
namely a 2s2p (board with a power and a ground plane) and vias attaching the thermal balls to the ground
plane.
7.4
When the board temperature is not known, a thermal simulation of the application is needed. The simple
two-resistor model can be used with the thermal simulation of the application [2], or a more accurate and
complex model of the package can be used in the thermal simulation.
Freescale Semiconductor
θJC
is device-related and cannot be influenced by the user. The user adjusts the thermal environment to
R
R
R
R
T
P
D
B
θJA
θJC
θCA
θJB
Estimation with Junction-to-Case Thermal Resistance
Estimation with Junction-to-Board Thermal Resistance
Estimation Using Simulation
= board temperature (°C)
= power dissipation in package
= junction-to-case thermal resistance (°C/W)
= junction-to-board thermal resistance (°C/W)
= junction-to-ambient thermal resistance (°C/W)
= case-to-ambient thermal resistance (°C/W)
R
T
θJA
J
= T
= R
B
+ (R
θJC
MPC875/MPC870 PowerQUICC™ Hardware Specifications, Rev. 4
θJB
+ R
θCA
× P
D
)
θCA
. For instance, the user can change the airflow around
Thermal Calculation and Measurement
13