US 6,603,692 B2Granted

Semiconductor memory device improving data read-out access

AssigneeNEC Electronics Corporation

InventorTakuya Hirota

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Abstract

A semiconductor memory device, capable of being accessed at a high speed, according to the present invention, is provided, and is configured with the changeover point in time between the pre-charge operation and a word line selection operation on the far-end side of the sense amplifier being earlier than that on the near-end side of it. There are provided word selection signal input buffer, block selection signal input buffer, digit selection signal input buffer on semiconductor chip, decoders, which decode the said signals, drivers for the output signal of each decoder, memory block, which is stored with information, and gate circuit, which selects a column of memory cells in a memory block. Drivers for the word selection signal and block selection signal are laid out in the middle of chip and near far-end side pre-charge unit, which is located the farthest from the sense amplifier (which is deployed in near-end side pre-charge unit.

Claims6

Dependent claims

A semiconductor memory device, comprising:

a plurality of memory cells;
a digit line connected to each memory cell and having first and second ends;
a plurality of word lines each crossing said digit line and each coupled to an associated one of said memory cells;
a word driver for activating one of said word lines that corresponds to a content of a word selection signal;
an input buffer coupled to receive said word selection signal;
a first pre-charge circuit arranged on a side of said first end of said digit line;
and
a second pre-charge circuit arranged on a side of said second end of said digit line;
a sense amplifier arranged near to said first pre-charge circuit;
said word lines including a first word line near to said first pre-charge circuit and a second word line near to said second pre-charge circuit;
wherein a period of time from said input buffer receiving a first word selection signal to activation of said second word line is shorter than a period of time from said input buffer receiving a second word selection signal to activation of said first word line.

8 more elements

Dependencies are inferred from the claim text.