A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

An improved sensing circuit is disclosed that utilizes a bit line in an unused memory array to provide reference values to compare against selected cells in another memory array. A circuit that can perform a self-test for identifying bit lines with leakage currents about an acceptable threshold also is disclosed.

An improved sensing circuit is disclosed that utilizes a bit line in an unused memory array to provide reference values to compare against selected cells in another memory array. A circuit that can perform a self-test for identifying bit lines with leakage currents about an acceptable threshold also is disclosed.

Sensing in non-volatile memory is performed using bias conditions that are dependent on the position of a selected memory cell within a group of non-volatile memory cells. During sensing, a selected memory cell receives a reference voltage while the remaining memory cells receive a read or verify pass voltage. For at least a subset of the unselected memory cells, the pass voltage that is applied is dependent upon the position of the selected memory cell in the group. As programming progresses from a memory cell at a first end of a NAND string toward a memory cell at a second end of the NAND string, for example, the pass voltage for at least a subset of the unselected memory cells that have already been subjected to programming may be increased. This technique may reduce the effects of an increased channel resistance that occurs as more memory cells are programmed.

Sensing in non-volatile memory is performed using bias conditions that are dependent on the position of a selected memory cell within a group of non-volatile memory cells. During sensing, a selected memory cell receives a reference voltage while the remaining memory cells receive a read or verify pass voltage. For at least a subset of the unselected memory cells, the pass voltage that is applied is dependent upon the position of the selected memory cell in the group. As programming progresses from a memory cell at a first end of a NAND string toward a memory cell at a second end of the NAND string, for example, the pass voltage for at least a subset of the unselected memory cells that have already been subjected to programming may be increased. This technique may reduce the effects of an increased channel resistance that occurs as more memory cells are programmed.

A memory device includes a high density or 3D data memory and a 3D reference memory. The reference memory is used to generate a reference signal used to sense data in the data memory. Conversion circuitry converts signals from one memory cell or a group of memory cells in the reference memory into a reference signal. The reference signal is applied to a sense amplifier to sense data stored in a selected memory cell in the data memory.

A memory device includes a high density or 3D data memory and a 3D reference memory. The reference memory is used to generate a reference signal used to sense data in the data memory. Conversion circuitry converts signals from one memory cell or a group of memory cells in the reference memory into a reference signal. The reference signal is applied to a sense amplifier to sense data stored in a selected memory cell in the data memory.

A non-volatile memory (NVM) includes at least one memory unit region, each including a memory array and having first memory cells in the odd columns and second memory cells in the even columns. Corresponding to each memory unit region, the NVM includes a multiplexer including first bit line decoders and second bit line decoders, a comparator circuit including a first input terminal and a second input terminal, and a bias generation circuit generating a bias voltage. When reading a data information from a first memory cell, a first output voltage of the first memory cell is sent to the first input terminal and the bias voltage is sent to the second input terminal. When reading a data information from a second memory cell, a second output voltage of the second memory cell is sent to the second input terminal and the bias voltage is sent to the first input terminal.

A non-volatile memory (NVM) includes at least one memory unit region, each including a memory array and having first memory cells in the odd columns and second memory cells in the even columns. Corresponding to each memory unit region, the NVM includes a multiplexer including first bit line decoders and second bit line decoders, a comparator circuit including a first input terminal and a second input terminal, and a bias generation circuit generating a bias voltage. When reading a data information from a first memory cell, a first output voltage of the first memory cell is sent to the first input terminal and the bias voltage is sent to the second input terminal. When reading a data information from a second memory cell, a second output voltage of the second memory cell is sent to the second input terminal and the bias voltage is sent to the first input terminal.

Disclosed are methods, systems and devices for generation of a read signal to be applied across a load for use in detecting a current impedance state of the load. In one implementation, a voltage and current of a generated read signal may be controlled so as to maintain a current impedance state of the load.