摘要:
According to one embodiment, a system includes a memory, a controller which controls an operation of the memory in a data program, and data bus which connects the memory to the controller. The memory comprises a memory cell array with memory cells which have a bit assignment to 2x (x is an integer number of 3 or more) threshold distributions, each memory cell storing x bits, and a control circuit which controls the data program of x bits to the memory cells. The controller comprises a first step generating y bit (y is an integer number and y
摘要:
According to one embodiment, a system includes a memory, a controller which controls an operation of the memory in a data program, and data bus which connects the memory to the controller. The memory comprises a memory cell array with memory cells which have a bit assignment to 2x (x is an integer number of 3 or more) threshold distributions, each memory cell storing x bits, and a control circuit which controls the data program of x bits to the memory cells. The controller comprises a first step generating y bit (y is an integer number and y
摘要:
A nonvolatile semiconductor storage apparatus comprises a memory cell array having a plurality of memory cells which are connected to word lines and to bit lines and in each of which different information of x (x is an integer equal to or larger than 3) bits is stored in association with 2x threshold voltages, the x-bit information being able to be read from each memory cell by applying a read voltage to the corresponding word line; a row decoder connected to the word lines to supply voltages to the word lines to operate the memory cells; and a sense amplifier device connected to the bit lines to read data stored in the memory cells and to hold the read data and data written to the memory cells, wherein the x-bit information corresponding to a certain threshold voltage differs from that corresponding to the adjacent threshold voltage by only 1 bit, 2x−1 of the read voltages are each set for a pair of adjacent threshold voltages, and applying any of the read voltages to the word line determines the x-bit information stored in the memory cell, and at least two read voltages are set in order to determine information for each of the x bits.
摘要:
A semiconductor memory device includes a memory cell array with memory cells arranged therein, each memory cell storing data defined by threshold voltage thereof, wherein the memory cell array includes first and second areas; the first area stores multi-value data written with plural write steps; and the second area stores binary data defined by first and second logic states, threshold levels of which are controlled through the plural write steps adapted to the multi-value data write.
摘要:
In a memory cell array, memory cells enabled to store plural-bit data are arranged in matrix. The bit-line control circuit is connected to bit-lines to control the bit-lines. A word line control circuit applies a plural-bit data read voltage as a word line voltage to the word line. The plural-bit data read voltage is larger than an upper limit of one of plural threshold voltage distributions and smaller than a lower limit of another threshold voltage distribution. Furthermore, it applies a soft-value read voltage as a word line voltage to the word line. The soft-value read voltage is smaller than an upper limit of a threshold voltage distribution and larger than a lower limit thereof. The likelihood calculation circuit calculates likelihood of the plural-bit data stores in the memory cells based on the soft-value.
摘要:
A write controller performs verification for checking whether each memory cell is on a predetermined verification level. For a memory cell to be written to a voltage level higher than the predetermined verification level, the write controller stores, in first and second latch circuits, the number of times of write to be performed by a write voltage after the verification. Whenever write is performed by the write voltage, the write controller updates the number of times of write stored in the first and second latch circuits. After write is performed the number of times of write by the write voltage, the write controller performs write by an intermediate voltage lower than the write voltage.
摘要:
A semiconductor memory device executes a writing operation based on a first bit assignment pattern at the time of writing. The first bit assignment pattern is created such that pieces of x-bit data assigned to adjacent threshold distributions have only a one-bit difference therebetween and an alignment of data on the same digit of 2x pieces of x-bit data corresponding to an alignment of 2x pieces of threshold distributions contains at least two transition points of “0” and “1”. The semiconductor memory device operates at the time of reading such that a read voltage corresponding to the transition points of “0” and “1” is applied to the word line on a page basis to determine x-bit data stored in the memory cell one-bit by one-bit based on the first assignment pattern. The page contains a set of data on the same digit bit in pieces of x-bit data stored in the memory cells connected to the word line.
摘要:
A semiconductor memory device includes: a memory cell array having a plurality of memory cells arranged therein; and a sense amplifier circuit configured to read data of the memory cell array, wherein a comparison operation is performed between read out data from the memory cell array and externally supplied expectance data in the sense amplifier circuit.
摘要:
A semiconductor memory device executes a writing operation based on a first bit assignment pattern at the time of writing. The first bit assignment pattern is created such that pieces of x-bit data assigned to adjacent threshold distributions have only a one-bit difference therebetween and an alignment of data on the same digit of 2x pieces of x-bit data corresponding to an alignment of 2x pieces of threshold distributions contains at least two transition points of “0” and “1”. The semiconductor memory device operates at the time of reading such that a read voltage corresponding to the transition points of “0” and “1” is applied to the word line on a page basis to determine x-bit data stored in the memory cell one-bit by one-bit based on the first assignment pattern. The page contains a set of data on the same digit bit in pieces of x-bit data stored in the memory cells connected to the word line.
摘要:
A semiconductor memory device includes: a memory cell array having a plurality of memory cells arranged therein; and a sense amplifier circuit configured to read data of the memory cell array, wherein a comparison operation is performed between read out data from the memory cell array and externally supplied expectance data in the sense amplifier circuit.