Hi Simba,
The HBENDB15/BYTESEL & DB14/HBEN are digital pins. I would suggest putting a pull up resistor when connecting this pin directly to Vdrive . This is to protect the part specially when there is another trace connected to this pin, which can change the pin to lo (ground), if this happened, Vdrive will have a direct connection to the ground. You may also want to check the AD7606 evaluation board user guide for your reference like on the RANGE (pin 8) and PAR/SER/BYTE (pin6) pins of the schematic.
Regards,
Jonathan