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604 Hardware Specifications

Preliminary/Subject to Change without Notice

Assuming an air velocity of 1 m/s, we have an effective Rsa of 3 °C/W, thus

Tj = 30°C + 5°C + (0.03 °C/W +1.0 °C/W + 3 °C/W) * 18 W,

resulting in a junction temperature of approximately 107

°C which is more than the maximum operating

temperature of the part. To ensure maximum reliability, it is desirable to operate the 604 well within its

operating temperature range. Thus, to keep an 18-watts 604 within its proper operating range, an air velocity

greater than 1 m/s should be used with the Thermalloy #2333B pin-fin heat sink.

Other heat sinks offered by Thermalloy, Aavid, Wakefield, and IERC offer different heat sink-to-ambient

thermal resistances, and may or may not need air flow. It is necessary to perform an analysis as done above

to select the desired heat sink.

Though the junction-to-ambient and the heat sink-to-ambient thermal resistances are a common figure-of-

merit used for comparing the thermal performance of various microelectronic packaging technologies, one

should exercise caution when only using this metric in determining thermal management because no single

parameter can adequately describe three-dimensional heat flow. The final chip-junction operating

temperature is not only a function of the component-level thermal resistance, but the system-level design

and its operating conditions. In addition to the component's power dissipation, a number of factors affect the

final operating die-junction temperature. These factors might include airflow, board population (local heat

flux of adjacent components), heat sink efficiency, heat sink attach, next-level interconnect technology,

system air temperature rise, etc.

Due to the complexity and the many variations of system-level boundary conditions for today's

microelectronic equipment, the combined effects of the heat transfer mechanisms (radiation, convection and

conduction) may vary widely. For these reasons, we recommend using conjugate heat transfer models for

the board as well as system-level designs. To expedite system-level thermal analysis, several “compact”

thermal-package models are available within FLOTHERM®. These are available upon request.

1.9 Ordering Information

This section provides the part numbering nomenclature for the 604. Note that the individual part numbers

correspond to a specific combination of 604 internal/bus frequencies, which must be observed to ensure

proper operation of the device. For available frequency combinations, contact your local Motorola or IBM

sales office.

In addition to the processor frequency and bus ratio, the part numbering scheme also consists of a part

modifier. The part modifier allows for the availability of future enhanced parts (that is, lower voltage, lower

power, higher performance, etc.).

Each part number also contains a revision code. This refers to the die mask revision number and is specified

in the part numbering scheme for identification purposes only.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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