I think that I will use AD8591.
Please let me know the threshold voltage of a shutdown inputs, when using at 3.3V.
There is only a value of 2.7V and 5V in a data sheet.
Thank you for considering AD8591 in your design. AD8591 conforms to the standards logic level set in the industry. Please see attachment for the different Standard Logic Levels. For 3.3V, VINH=2.0V while VIN=0.8V approximately. It is recommended though that you should operate your logic inputs near to the voltage rails so your design could be less susceptible to errors due to noise.
You may be interested in this Mini Tutorial about Low Voltage Logic Interfacing.
Hope this helps.
Thank you for making the time for my question.