Can PDB and PDB2 be tied together without loss in amp-to-amp isolation? Are these truly digital inputs? I want to run these enable pins off of the 5V I'm using for powering the chip. I will use a voltage divider with a 10K from 5V to these pins and a 15K from these pins to ground. This should give me a 3V input for these pins. As an alternative, the data sheet says they are internally pulled up to 2.8V so can I just leave these open to enable the amps? What does ADI recommend?