Abstract: Bit lines connected to each nonvolatile memory cell are selected by corresponding selective transistors. A first drive circuit for driving the gate of one of the selective transistors receives a voltage selected by a first voltage switch, and a second drive circuit for driving the gate of the other selective transistor receives a voltage selected by a second voltage switch. A transistor constituting the first drive circuit is different in structure from a transistor constituting the second drive circuit.

Abstract: In a semiconductor memory device, the output of a regulator is coupled to the inputs of first and second switches, the output of the first switch is coupled to a path for supplying the drain voltage of a memory cell in the first mode, and the output of the second switch is coupled to a path for supplying the gate voltage of the memory cell in the second mode. A fourth switch is placed in parallel with the second switch: the output of the fourth switch is coupled to the output of the second switch, to supply the gate voltage of the memory cell in the first mode. Thus, one regulator is used as both the regulator for the drain voltage of the memory cell and the regulator for the gate voltage of the memory cell.

Abstract: In a non-volatile semiconductor memory device, variations in voltage applied to a bit line when an erase voltage applying step is repeatedly executed are suppressed, thereby reducing variations in Vt after erasure. A memory array includes memory cells arranged in an array, a plurality of word lines, and a plurality of bit lines and main bit lines. The memory array also includes a usable region which can store data and an isolation region which cannot store data. Each bit line provided in the usable region is connected via a select transistor to the corresponding main bit line. At least one main bit line is connected not only to a bit line of the usable region, but also to a bit line of the isolation region via a select transistor.

Abstract: In a semiconductor memory device, a voltage rise due to IR-DROP is suppressed which occurs when a ground voltage is applied to a memory cell during a program operation. Discharge transistors are provided between the ground and bit lines connected to the source and drain of the memory cell. The discharge transistors receive mutually independent discharge control signals which are generated and outputted from a DS decoder driver at the respective gates thereof. To the bit line which applies the ground voltage to the memory cell, the ground voltage can be set using the discharge transistor.

Abstract: In a semiconductor memory device, a voltage rise due to IR-DROP is suppressed which occurs when a ground voltage is applied to a memory cell during a program operation. Discharge transistors are provided between the ground and bit lines connected to the source and drain of the memory cell. The discharge transistors receive mutually independent discharge control signals which are generated and outputted from a DS decoder driver at the respective gates thereof. To the bit line which applies the ground voltage to the memory cell, the ground voltage can be set using the discharge transistor.

Abstract: In a non-volatile semiconductor memory device, variations in voltage applied to a bit line when an erase voltage applying step is repeatedly executed are suppressed, thereby reducing variations in Vt after erasure. A memory array includes memory cells arranged in an array, a plurality of word lines, and a plurality of bit lines and main bit lines. The memory array also includes a usable region which can store data and an isolation region which cannot store data. Each bit line provided in the usable region is connected via a select transistor to the corresponding main bit line. At least one main bit line is connected not only to a bit line of the usable region, but also to a bit line of the isolation region via a select transistor.

Abstract: A drain voltage generator circuit includes a first switching element coupled between a first power supply voltage and an output end of the drain voltage generator circuit, a second switching element coupled in parallel to the first switching element and having a smaller current capability than that of the first switching element, and a control circuit for turning ON the second switching element and then the first switching element, and generates a voltage to supply to a drain of a memory cell. A source of the memory cell is set to be floated or grounded by a transistor.