Semiconductor memory device including pass transistors with variable sizes

Abstract

A semiconductor memory device includes a memory cell array (MCA) and a pass transistor unit (PTU). The MCA includes memory block(s) that has source selection line(s) (SSL), word lines (WLs), drain selection line(s) (DSL), and dummy WL(s) (DWL). The PTU includes source pass transistor(s) to selectively transmit a source driving signal (source DS) to the SSL, memory pass transistors (MPTs) to selectively transmit a WL DS to the WLs, respectively, drain pass transistor(s) (PT) to selectively transmit a drain DS to the DSL, and dummy PT(s) to selectively transmit a DWL DS to the DWL. The source DS, the WL DS, the drain DS, and the DWL DS may each be associated with a respective voltage range. Sizes of the source PT, the MPTs, the drain PT, and the dummy PTs are set based on the respective voltage ranges.