An apparatus, comprising: a substrate; a coupling capacitor that is formed over the substrate; and an isolator that is formed between the substrate and the coupling capacitor, the isolator including: (a) an MP-well layer, (b) a first well layer, (c) an epi tub layer that is nested in the MP-well layer and the first well layer, and (d) a second well layer that is nested in the epi tub layer.