Abstract: One interface chip and a plurality of core chips are electrically connected via a plurality of through silicon vias. A data signal of a driver circuit is input into the core chip via any one of the through silicon vias. An output switching circuit activates any one of tri-state inverters and selects one of the through silicon vias. The tri-state inverters amplify the data signal and transmit it to the through silicon via. Similarly, an input switching circuit activates any one of tri-state inverters. These tri-state inverters also amplify the data signal transmitted from the through silicon via and supply it to the receiver circuit.