ADUM5402 Regulator Issue

Hi there,

I'm having an issue with an ADUM5402 Regulator.  Upon power-up, the Primary side voltage is present, however the Isolated side does not output the isolated voltage.  Upon probing the circuit to troubleshoot the issue the isolated voltage appears.  Afterwards, the isolator will not fail even after power cycle and complete discharge.

It looks like the regulator has stalled and the small amount of capacitance from the probe has kicked it into operation.

I have been able to recreate this issue on a couple of our boards.

This circuit is in a fairly low load situation.  The Viso is powering an RS422 Transceiver (0.8mA typical)  that is using only the receive buffer.

Any help would be greatly appreciated.

Regards,

Scott