Semiconductor memory device and method for controlling its output
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsKoichi Nagase, Akio Nakayama, Tetsuya Aono, Yutaka Ikeda, Yoshinori Mizugai
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Abstract
An upper column address strobe signal and a lower column address strobe signal applied to a dynamic RAM are 180.degree. out of phase from each other. Data of n bits are read out from a memory cell array at a time. The data read out from memory cell array is divided into two bit groups and applied to an upper IO buffer and a lower IO buffer. Upper IO buffer and lower IO buffer latch sequentially the upper bit group and the lower bit group and output these groups to a data transmission bus in response to the upper column address strobe signal and the lower column address strobe signal.
Claims5
A semiconductor memory device from which data of n (n is an integer equal to or larger than 2) bits can be read out simultaneously from a memory cell array including a plurality of memory cells, comprising:
- selection means for simultaneously selecting n memory cells in said memory cell array based on externally applied address data;
- and
- outputting means for dividing data of n bits read out from the n memory cells selected by said selection means into a plurality of bit groups and for sequentially outputting the plurality of bit groups in response to a plurality of externally applied timing signals which are out of phase with each other.
A method of controlling output of a semiconductor memory device permitting reading of data of n (n is an integer equal to or larger than 2) bits simultaneously from a memory cell array including a plurality of memory cells, comprising:
- a first step of externally applying a plurality of timing signals out of phase from each other to the semiconductor device;
- and
- a second step of dividing the data of n bits read out from said memory cell array into a plurality of bit groups and sequentially outputting the divided bit groups in response to said plurality of timing signals.
Dependencies are inferred from the claim text.