A NOR-type flash memory device includes a global decoder circuit that is
coupled to global wordlines. The global decoder circuit drives the global
wordlines using wordline voltages that will be applied to local wordlines
in each operation mode, and has wordline select switches each
corresponding to the global wordlines. A local decoder circuit couples the
local wordlines to the global wordlines in response to a sector select
signal, and a sector generates a control signal in accordance with address
information for selecting a memory cell array. A switch circuit includes a
plurality of depletion MOS transistors each being coupled between
corresponding first and second wordline. The depletion MOS transistors are
commonly controlled by a control signal. Each of the wordline select
switches is made of two NMOS transistors.
