I would like to take full advantage of the ADC's input range while using the internal buffers.
I have configured the ADC to run from a single +3.3V supply.
If the internal buffers are turned on, the absolute analog input range become 0 to 2.2V.
If I use a 1.1V external reference, the ADC range will match the absolute analog input range.
I don't think I want to use a resistor divider off of the ADR441 to create a 1.1V reference.
Should I buffer this signal with an amplifier for the reference?
I don't think the ADR512 is a suitable replacement.
It has 4x the output noise; 20x the temperature coefficient.
I noticed that the ADR441 is used on the evaluation board and that there appears to be a resistor divider between the output of the part and the input of reference inputs.
I'm thinking about inserting an amplifier in a non-inverting configuration with a gain of 0.44 to create the 1.1V reference from the 2.5V reference output of the ADR441. Is this a suitable approach to the problem and if so what amp would you reccommend?
I'm thinking a low input bias current amp like the AD8615 would do the job.
What are your thoughts?