we are using an AD7357 and an AD8132 to drive the inputs of the AD7357. Trouble is, we see large voltage swings at the Vin+ and Vin- of the AD7357 which are not related to the signal we feed into the AD8132. We use pretty much the recommended circuit, place the output resistors quite close (5mm) to the input of the AD7357.
The large voltage swings look like cross-talk from the digital part of the AD7357.
We are puzzled - since the output of the AD7357 is quite ok.
However, we would like to impose as little noise as possible and are concerned that the voltage swings degrade our quality and we could obtain a much better signal. Furthermore, we measure a signal drift after the AD7357 which we cannot explain.
Any help is appreciated