An external charger for an implantable medical device, comprises a housing, an alternating current (AC) coil and substrate contained within the housing, and one or more electronic components mounted to the substrate. The AC coil is configured for wirelessly transmitting magnetic charging energy to the implantable medical device. The AC coil is disposed in a first plane, with the magnetic charging energy having a field directed perpendicular to the first plane. At least a portion of the substrate has a surface extending along a second plane that is substantially perpendicular to the first plane.