Continuation . . .

The problems relating to thermal and mechanical stress resistance, mentioned at the beginning, are more critical.

Ceramic materials are well known for their ability to stand up to high temperatures and for their mechanical reliability concerning resistance to pressure. However, for the use of large size codes, a more critical factor is the well-known brittleness of ceramics. The considerable mechanical-thermal stress on SMD components during processing and application, discussed at the beginning, poses problems for SMD-ceramic capacitors in large size codes too.

Substrate Bending Test

An important criterion for testing practical use in applications is the substrate bending test. In this test, SMD components are soldered on to a 100mm x 30mm printed circuit test board standardized, for example, in accordance with IEC 60068-2-21, under real processing conditions. The printed circuit test board is subjected to bending of 1mm to 5 mm by means of a special tool.

Picture 2: Test configuration in accordance to IEC 60068-2-21