Semiconductor storage device and information apparatus

Abstract

A semiconductor storage device includes: a memory array including a plurality of memory cells; a reference array including a plurality of reference cells; a decoder section for selecting a memory cell from the memory cells and a reference cell from the reference cells based on address information; and a comparison / output section for comparing a read voltage level from the memory cell selected by the decoder section and a read voltage level from the reference cell selected by the decoder section so as to output a result of the comparison in the form of data, wherein the decoder section simultaneously outputs a selection signal to a word line of the memory cell and a selection signal to a word line of the reference cell.

Description

technical field [0001] The present invention relates to a nonvolatile memory in which data is electrically writable (for example, a semiconductor storage device such as flash EEPROM, etc.), and to information equipment using the nonvolatile memory, such as a cellular phone terminal and the like. Background technique [0002] Conventionally, in a nonvolatile semiconductor storage device (nonvolatile memory such as flash EEPROM) in which data is electrically writable, a data read operation is performed as follows: Figure 8 As shown, the same drain voltage is applied to the memory cell RC0 (which is called a "reference cell") set at a predetermined threshold value, and to the memory cell MC0 of the memory array on which the data read operation is performed. , while the same gate voltage is applied by the reference word line decoder and the normal word line decoder, and the difference between the current values ​​flowing through the memory cells RC0 and MC0 is sensed by the sens...

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Problems solved by technology

[0055] However, if unwanted data is once output immediately after the sensing start time (time t(a)), in many cases, additional time is consumed until desired data is successfully output.

This extra time is quite long, especially when the redundant word line is selected, because as mentioned above, it takes a certain length of time in order to switch from the normal word line to the redundant word line

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