A microelectronic assembly can include a microelectronic device, e.g., semiconductor chip (910), connected together with an interconnection element (930), e.g., substrate, the latter having signal contacts (990) and reference contacts (980). The reference contacts can be connectable to a source of reference potential such as ground or a voltage source other than ground such as a voltage source used for power. Signal conductors, e.g., signal wirebonds (965) can be connected to device contacts (912) exposed at a surface of the microelectronic device (910). Reference conductors, e.g., reference wirebonds (975) can be provided, at least one of which can be connected with two reference contacts (980) of the interconnection element (930).; The reference wirebond (975) can have a run which extends at an at least substantially uniform spacing from a signal conductor, e.g., signal wirebond (965) that is connected to the microelectronic device over at least a substantial portion of the length of the signal conductor. In such manner a desired impedance may be achieved for the signal conductor.