Patent ID: 6956780

Claim:
A semiconductor memory device comprising: a bitline sense amplifier adapted to sense-amplify data of a pair of bitlines; a pair of complementary local input/output lines; a pair of column select switches connected between the bitline sense amplifier and the pair of complementary local input/output lines, said column select switches being adapted to respond to a column select signal; a pair of complementary global input/output lines; a pair of write control switches connected between the pair of complementary local input/output lines and the pair of complementary global input/output lines, said write control switches being adapted to respond to a write control signal; and a direct sense amplifier connected to the pair of complementary local input/output lines and the pair of complementary global input/output lines, said direct sense amplifier being adapted to generate a voltage difference, corresponding to a voltage difference between the pair of complementary local input/output lines, between the pair of complementary global input/output lines in response to a read control signal, said direct sense amplifier comprising, a first direct sense amplifier switch having a first end connected to a first one of the complementary global input/output lines, and being adapted to respond to a signal on a first one of the complementary local input/output lines; a second direct sense amplifier switch having a first end connected to a second end of the first direct sense amplifier switch, and having a second end connected to ground, and being adapted to respond to the read control signal; a third direct sense amplifier switch having a first end connected to a second one of the complementary global input/output lines, and being adapted to respond to a signal on a second one of the complementary local input/output lines; and a fourth direct sense amplifier switch, having a first end connected to a second end of the third direct sense amplifier switch, and having a second end connected to ground, and being adapted to respond to the read control signal.