I'm working with an AD7983 and hoping to get more information regarding the internal functionality of the REF pin. The datasheet describes how to use this pin from a top-level perspective, but I'm looking for a more technical description.
How does it interface with the internals of the ADC? Is there an example schematic to better describe this?
What are the effects on the internal circuitry as the reference voltage increases/decreases?
Does the pin have any protection from transients?
The REF pin has limited voltage input, as per table 5 Abs Max rating , it is limited to -0.3V to 6V, putting a voltage beyond can damage the part. The AD7983 voltage reference pin can operate from 2.9V to 5.1V. Figure 21 shows the internal circuitry of the bit weighted SAR ADC. The Ref pin is important in the ADC conversion. All conversion are referred to this voltage. If there is unstable reference, this would affect the AD7983 conversion result. It can have errors or wrong data result. The ADC requires 500uA at 1.33MSPS. Please make sure the reference that will be use is capable of driving the amount of current. And also don't forget to place a decoupling cap, 10uF as recommended. This will act as reservoir cap between conversion.