Miniature feedthroughs leave room for expansion

Thunderline-Z has developed a miniature hermetic glass feedthrough with a body height of just 0.89mm - a size reduction of around 13%.

For many designers of custom high-frequency assemblies, maintaining tight pitch (less than 2.54mm) between feedthroughs is critical to layout and performance issues.

The drawback of this tight pitch is that it sometimes results in excessive stress on the glass seal because of thermal expansion.

With sufficient unrestrained expansion, the glass seal may crack within the body of the feedthrough requiring removal and rework.

A single feedthrough failure in a tight-pitch row often requires the removal of adjacent feedthroughs in the row.

Thunderline-Z has solved this problem with the development of a miniature hermetic glass feedthrough with a body height that is just 0.89mm.

This is a size reduction of approximately 13% from an average feedthrough body used in these applications.

This compact body allows the glass seal to be recessed into the housing while maintaining the same wall thickness and hole configuration, thereby eliminating the excessive thermal stress on the glass seal.

The redesigned feedthrough promotes a more robust seal in "problem housings" where housings have already been machined and require the same hole-configuration and wall thickness as the standard feedthrough.

An additional benefit is that these feedthroughs allow for a solder schedule of up to 290C.

This high temperature rating increases solder schedule flexibility across the whole module and helps to reduce final inspection time.

The updated feedthroughs are ideal for a variety of applications where maintaining tight spacing between feedthroughs is critical.

They are in use today in Thunderline-Z's SolderTight custom packages.

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