ADUM5211 VDD2 lower than expected

I'm using the ADUM5211 Isolater and ADA4528-2 Dual Op-Amp to make an isolated current loop.  My circuit is below.  Unfortunately, when I apply 5V to the 5V0 net and 0V to the nEN pin, the 5V0ISO net is 2.3V (I expected to get 5V).

Is there anything obviously wrong with this circuit?  What troubleshooting steps might help me diagnose this?


Adam J.