A pad array electronic device for mounting on a substrate, such as a printed circuit board (PCB), has a relatively rigid package body with a plurality of holes bearing connecting mechanisms for bonding to lands on the PCB. The package body may be a thermoset plastic or other material that can be injection molded around an electronic component, such as an integrated circuit (IC) bonded to a lead frame. An integrated circuit die or other electronic component is mounted in proximity with or on the lead frame and electrical connections between the integrated circuit chip and the frame are made by any conventional means. In one aspect, the substrate leads are provided at their outer ends that are exposed by holes in the package with solder balls or pads for making connections to the PCB. The package body may be optionally used to stand off the device a set distance from the PCB so that the solder balls will form the proper concave structure. The periphery of the package body may function as a carrier structure to protect the lead or connection structures during testing, handling and board mounting. The open vias permit back side testing of the device before or after mounting of the package to the PCB. Additionally, a heat sink structure and/or capacitor may be directly bonded to the side or the top of the pad array electronic device which may be used singly or in multiple, stacked configurations, to facilitate the thermal dissipation from the device.