UL 1557:2018 PDF Download

The UL 1557:2018 standard provides requirements for semiconductor devices of the isolated-mounting type. This includes thyristors, transistors, diodes, and hybrid modules that consist of combinations of these devices.

The standard does not cover snubber and commutation circuits associated with thyristors, transistors, or other analog semiconductor devices.

It focuses on the isolation performance of these semiconductor devices and their combination in module packages. The constructional features relevant to achieving the desired isolation performance are also addressed.

It is important to note that compliance with these requirements does not automatically guarantee the acceptability of the isolated semiconductor for use as a component in an end product. The suitability of the semiconductor for a specific product depends on its performance under the actual service conditions it will encounter. Further investigation is necessary to determine its acceptability in such applications.