The ADuM144X family contains Schmitt trigger input buffers, which provide
hysteresis for noise rejection. During an input transition a Schmitt trigger
will introduce a small shoot-through current while the input is near the
mid-supply level. In devices with higher average power dissipation this is not
noticeable, but in ultra-low power parts like the ADuM144X it can be large
compared to the average supply current. It is recommended that the inputs be
driven with 0.5 V of VDD and GND to achieve the lowest power dissipation.