Good morning! I am using two AD7988-5 parts in a chain mode as seen in datasheet figure 38. VREF and VDD (pins 1 and 2) are connected to a 2.5V source that is turned on when data collections are required otherwise it is 0V (low duty cycle every minute). VDDIO (pin 10) is connected 3.3V source that is always powered. I have a 100 kohm pullup on the Conversion pin 6 to VDDIO and a 100 kohm pulldown on the Sck pin 8.
My question is this....I am trying to have NO power consumed at all until I turn the 2.5V (VREF/VDD) power on. Since VDDIO is always powered are SDO and SCK driven as totem pole outputs such that they never float?