A digital-to-analog converter has a plurality of current cells. The positioner can automatically move the collector in multiple dimensions to collect objects into the collector according to a specified collection pattern. The network interface unit receives a stream of packets from a transmission device. The UBM layer can be formed on the protective layer and can directly make contact with the pad and the guard ring. A plurality of the wires extend along a radial direction of a phantom circle having a center on the circuit board.