I'm a DFAE in Japan. Our customer evaluates AD8029. According to the data sheet on page19, it says "Using a multilayer board with an internal ground plane can help reduce ground noise and enable a more compact layout.", on the other hand "On multilayer boards, all layers beneath the op amp should be cleared of metal to avoid creating parasitic capacitive elements." What is meaning "metal" ? Generally, the PCB uses copper which is a type of metal. Shouldn't there be a copper ground plane under the op amp?