Ensure that the PWB has an internal ground plane that extends under the DLPA300. All nine ground pins (1, 7, 14, 20, 41, 46, 53, 55, and 60) must be connected to the ground plane using the shortest possible runs and vias. All filter and bypass capacitors must be placed near the pin being filtered or bypassed for the shortest possible runs to the part and to the ground plane.