The ADuM5401W-1/ADuM5402W-1/ADuM5403W-1 versions of the isolators provide an
upgraded voltage reference to ensure proper startup under all load conditions.
Please refer to page 23 of the latest REV E of the ADuM5402 datasheet. This
page provides a detailed description of the startup issues which were found on
the ADuM540x devices and it also documents the restrictions which apply to the
use of ADuM540x to avoid or provide a workaround for the startup problem.
Because of the upgraded voltage reference, these restrictions do not apply to
the ADuM5401W-1/ADuM5402W-1/ADuM5403W-1 devices and this is why we recommend
the -1 devices for new designs. Nothing else on the datasheet has changed.