When work in shutdown mode, output pins are abnormal and DC power is larger
than other mode. DB7: high level(5V); BUSY: high; /CS: high; DC Power >100mA. I
use HOST to enter shutdown mode before power up AD7606.
if you want to use shutdown or standby mode, please firstly use resistors to
pull up RANGE and /STBY to VDRIVE. After power up, use HOST I/O to enter the
shutdown or standby mode.