28

PID6-603e Hardware Specifications, Rev 2

Heat sinks are attached to the package by means of a spring clip to holes in the printed-circuit board (see

Figure 14). This spring force should not exceed 5.5 pounds of force. Therefore, the synthetic grease offers

the best thermal performance, considering the low interface pressure. Of course, the selection of any thermal

interface material depends on many factors—thermal performance requirements, manufacturability, service

temperature, dielectric properties, cost, etc.

Figure 16. Thermal Performance of Select Thermal Interface Material

The board designer can choose between several types of thermal interface. Heat sink adhesive materials

should be selected based upon high conductivity, yet adequate mechanical strength to meet equipment

shock/vibration requirements. There are several commercially-available thermal interfaces and adhesive

materials provided by the following vendors:

Dow-Corning Corporation

517-496-4000

Dow-Corning Electronic Materials

PO Box 0997

Midland, MI 48686-0997

Chomerics, Inc.

617-935-4850

77 Dragon Court

Woburn, MA 01888-4850

0

0.5

1

1.5

2

0

1 02 0

3 04 05 06 07 08 0

Graphite/Oil Sheet (0.005 inch)

Silicone Sheet (0.006 inch)

Floroether Oil Sheet (0.007 inch)

Synthetic Grease

Bare Joint

Contact Pressure

(psi)

Contact Pressure (psi)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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