Semiconductor storage device, and method for reading stored data

Abstract

The invention aims to provide a semiconductor storage device with which it is possible to improve the reading properties of a sense amplifier. To also provide a method for reading stored data. A semiconductor storage device is provided with a sense amplifier and a controller. The sense amplifier has a first transistor for clamping the voltage of a bit line, a second transistor disposed between a reference voltage node and a voltage node clamped by the first transistor, and a third transistor inserted between a charge / discharge node and the voltage node clamped by the first transistor. In a first operation mode, the controller turns on the first transistor and the second transistor, and turns off the third transistor. The controller turns on the third transistor in a second operation mode, and in a third operation mode, the controller turns on the first transistor, turns off the second transistor, turns on the third transistor and turns on a fourth transistor.

Description

technical field [0001] Embodiments of the present invention relate to a semiconductor memory device and a method of reading stored data. Background technique [0002] As a large-capacity recording medium, a nonvolatile semiconductor storage device typified by a NAND-type flash memory is used in various electronic devices. Such a nonvolatile semiconductor memory device converts data read from selected memory cells into a desired voltage level via a sense amplifier (sense amplifier). The read operation of the sense amplifier is called sensing (sense, readout). [0003] As one of the sensing methods, the ABL (All Bit Line, All Bit Line) method is known. In the ABL method, after precharging the bit lines, a read operation is performed on all the bit lines. Then, based on the amount of current flowing from the bit line, read data from the memory cell is detected. [0004] In the ABL method, the bit line is precharged first. Then, the transistor connected to the sensing node ...

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Problems solved by technology

Therefore, it becomes the main cause of the deterioration of the read characteristic of the sense amplifier

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