semiconductor chip

UL1557 is a UL(Underwriters Laboratories) certification standard for electrically isolated semiconductor devices.

It is mainly suitable for isolation mounting type semiconductor devices, such as thyristors, transistors, diodes, etc., and hybrid modules composed of a combination of these devices. This standard covers the isolation performance of thyristors, transistors, diodes, etc., as well as their combination in the module package and the structural characteristics related to this performance.

• insulating material: UL1557 standard requires that the material between the charged body and the heat sink, or in direct contact with the charged body, needs to have an insulating effect. This includes housings, epoxy, silicone, etc. Usually the shell and epoxy need to use UL certified materials, but there is no special provision for silicone.

• temperature requirements: The standard also specifies the requirements for the external temperature (shell temperature) of the semiconductor part or package and the maximum junction temperature (junction temperature) of the semiconductor. These temperatures are also taken as the operating temperature of the insulating material. In addition, there is a requirement for a storage temperature, I .e. an acceptable semiconductor storage temperature under uncharged conditions.

• Test Item: UL1557 is used to evaluate the safety of semiconductor products, mainly through withstand voltage after high and low temperature aging. This includes the withstand voltage test, that is, according to the withstand voltage value specified by the manufacturer, after taking it out in a high and low temperature environment, immediately apply an AC high voltage of 48~62Hz for 60 seconds to determine whether it passes the test.