AD7685: Supplied with VDD, but Vref and Vio removed

Document created by analog-archivist Employee on Feb 23, 2016
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I use AD7685 with VDD=3.3V and Vref=Vio=1.8V.  When I remove power from Vref
and Vio but keep VDD at 3.3V:
Will this harm the IC in any way?
Will there be any voltage's present on SPI pins or will they be pulled hard low?
When Vref and Vio power is restored will there be voltage stabilization delays
or can I use the part as usual?


Removing the voltages from Vref and Vio pins will not damage the part ina any
way, but the part won't work without these supplies. Without an applied
reference voltage an input signal cannot be applied.
Note that the VIO and VDD can be tied together to reduce the number of supplies
needed and the AD7685 is
independent of power supply sequencing between VIO and VDD.
There shouldn’t be any voltage present on SPI if you don’t apply the voltage at
VIO pin.
The part should work normally when you apply all the required voltages within
the datasheet limits.