Thermal
16 Thermal
This section describes the thermal specifications of the MPC8540.
16.1 Thermal Characteristics
Table 59 provides the package thermal characteristics for the MPC8540.
Table 59. Package Thermal Characteristics
Characteristic
Symbol
Value
Unit
Notes
Junction-to-ambient Natural Convection on four layer board (2s2p)
Junction-to-ambient (@100 ft/min or 0.5 m/s) on four layer board (2s2p)
Junction-to-ambient (@200 ft/min or 1 m/s) on four layer board (2s2p)
Junction-to-board thermal
RθJMA
RθJMA
RθJMA
RθJB
16
14
°C/W
°C/W
•C/W
•C/W
•C/W
1, 2
1, 2
1, 2
3
12
7.5
0.8
Junction-to-case thermal
RθJC
4
Notes
1. Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site
(board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and
board thermal resistance
2. Per JEDEC JESD51-6 with the board horizontal.
3. Thermal resistance between the die and the printed-circuit board per JEDEC JESD51-8. Board temperature is
measured on the top surface of the board near the package.
4. Thermal resistance between the die and the case top surface as measured by the cold plate method (MIL SPEC-883
Method 1012.1). Cold plate temperature is used for case temperature; measured value includes the thermal
resistance of the interface layer.
16.2 Thermal Management Information
This section provides thermal management information for the flip chip plastic ball grid array (FC-PBGA)
package for air-cooled applications. Proper thermal control design is primarily dependent on the
system-level design—the heat sink, airflow, and thermal interface material. The recommended attachment
method to the heat sink is illustrated in Figure 44. The heat sink should be attached to the printed-circuit
board with the spring force centered over the die. This spring force should not exceed 10 pounds force.
MPC8540 Integrated Processor Hardware Specifications, Rev. 4
Freescale Semiconductor
79
FREESCALE [ Freescale ]
