An apparatus that includes: a control chip; a plurality of memory chips stacked on the control chip, the plurality of memory chips including first and second memory chips; and a plurality of via conductors connected between the plurality of memory chips and the control chip. Each of the first and second memory chips is divided into a plurality of channels including a first channel. The plurality of via conductors include a first via conductor electrically connected between the first channel in the first memory chip and the control chip, and a second via conductor electrically connected between the first channel in the second memory chip and the control chip. The first and second memory chips substantially simultaneously output read data read from the first channel to the first and second via conductors, respectively.