Datasheet
Table Of Contents
- 1 Overview
- 2 Features
- 3 Comparison with the MPC7447, MPC7445, and MPC7441
- 4 General Parameters
- 5 Electrical and Thermal Characteristics
- 6 Pin Assignments
- 7 Pinout Listings
- 8 Package Description
- 8.1 Package Parameters for the MPC7447A, 360 HCTE BGA
- 8.2 Mechanical Dimensions for the MPC7447A, 360 HCTE BGA
- 8.3 Package Parameters for the MPC7447A, 360 HCTE LGA
- 8.4 Mechanical Dimensions for the MPC7447A, 360 HCTE LGA
- 8.5 Package Parameters for the MPC7447A, 360 HCTE RoHS-Compliant BGA
- 8.6 Mechanical Dimensions for the MPC7447A, 360 HCTE RoHS-Compliant BGA
- 8.7 Substrate Capacitors for the MPC7447A, 360 HCTE
- 9 System Design Information
- 9.1 Clocks
- 9.2 PLL Power Supply Filtering
- 9.3 Decoupling Recommendations
- 9.4 Connection Recommendations
- 9.5 Output Buffer DC Impedance
- 9.6 Pull-Up/Pull-Down Resistor Requirements
- 9.7 JTAG Configuration Signals
- 9.8 Thermal Management Information
- Figure 20. BGA Package Exploded Cross-Sectional View with Several Heat Sink Options
- Figure 21. LGA Package Exploded Cross-Sectional View with Several Heat Sink Options
- 9.8.1 Internal Package Conduction Resistance
- 9.8.2 Thermal Interface Materials
- 9.8.3 Heat Sink Selection Example
- 9.8.4 Temperature Diode
- 9.8.5 Dynamic Frequency Switching (DFS)
- 10 Document Revision History
- 11 Ordering Information
MPC7447A RISC Microprocessor Hardware Specifications, Rev. 5
Freescale Semiconductor 43
System Design Information
9.8 Thermal Management Information
This section provides thermal management information for the high coefficient of thermal expansion
(HCTE) 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 MPC7447A implements
several features designed to assist with thermal management, including DFS and the temperature diode.
DFS reduces the power consumption of the device by reducing the core frequency; see Section 9.8.5.1,
“Power Consumption with DFS Enabled,” for specific information regarding power reduction and DFS.
The temperature diode allows an external device to monitor the die temperature in order to detect excessive
temperature conditions and alert the system; see Section 9.8.4, “Temperature Diode,” for more
information.
To reduce the die-junction temperature, heat sinks may be attached to the package by several
methods—spring clip to holes in the printed-circuit board or package, and mounting clip and screw
assembly (see Figure 20 and Figure 21); however, due to the potential large mass of the heat sink,
attachment through the printed-circuit board is suggested. In any implementation of a heat sink solution,
the force on the die should not exceed ten pounds.
Figure 20. BGA Package Exploded Cross-Sectional View with Several Heat Sink Options
NOTE
A clip on heat sink is not recommended for LGA because there may not be
adequate clearance between the device and the circuit board. A through-hole
solution is recommended, as shown in Figure 21 below.
Thermal
Heat Sink
HCTE BGA Package
Heat Sink
Clip
Printed-Circuit Board
Interface Material