Other Parts Discussed in Thread: REF3125
I'm using the ADS1258 with DVDD=3.3V, DGND=GND, AVDD=2.5V, and AVSS=-2.5V.
All of my inputs are AC/differential pairs, padded down from 9-10Vrms to put the voltage in range of the ADC. Lets assume a +/- 4V range for discussion (i.e. from +2 and -2 to -2 and +2)
The EVM/reference design has VREFN connected to ground, and the voltage reference between GND and VREFP, but that design does not have a bipolar supply. So I'm not sure how to handle the reference voltage for a bipolar supply. Do I keep VREFN connected to ground, with VREF being at 2V as half of 4V, or do I connect a 4V reference with VREFN connected to AVSS, making the reference from -2.5 to +1.5? Do I need some sort of floating reference between VREFN and VREFP independently, or are there bipolar references that I haven't seen?