A thermally stable material such as PTFE combines excellent thermal conductivity with a high dielectric constant, remaining stable over an unusually wide temperature range. Maintaining a good thermal dielectric constant can dramatically reduce changes in circuit impedance, RF reflection, and dead band shift.

Benefits for Military Computing

Figure 4. In the RF arena, the thermal stability of a board material plays a crucial roll in maintaining consistent and reliable operation over a wide temperature range.

The integration of single-sided, multilayer, and rigid-flex technologies with specialty materials can lower overall production costs by reducing or eliminating the need for conventional heatsinking systems. Additionally, the use of such materials and processes can provide improved longevity, reliability, and weight reduction

In most military-related work, we deal not only with commercial off-the-shelf (COTS) orders, but also with very specialized boards and unique computer applications. Commonly, the military is ahead of everyone, and when replacement parts are needed, they can be manufactured for many years. However, recently it has been increasingly harder to find parts.

This presents special problems that now can be solved through revisions. Newer parts are now smaller, faster, and hotter but can be incorporated into the replacement parts via a few alterations. The boards are used in specialty computers in high-speed, short-term use or in very long, intense usage in stressful environments. For this reason, the military is investigating thermal management more closely, particularly parts that can be made easier, faster, and more cost effectively.

This article was written by Brigitte Lawrence, owner of Brigitflex, a printed circuit board manufacturer in Elgin, IL. For more information, click here.