I've got a circuit that's not behaving as predicted by the AD8618 spice model included with LTSpice XVII (version 126.96.36.199).
It appears the common mode input capacitance (7.8pF according to the data sheet) is not included in the spice model. Nor does it seem to be in the AD8615 model I separately downloaded.
Anyway, it would have saved me a bit of time and effort if the common mode input capacitance was properly modeled. Please consider adding this to the model.
Or, you can tell me I'm all wet and I'll check my work again...but it sure looks to me like that's missing from the model.