Abstract: A plurality of memory types are distinguished from one another in memory systems containing a plurality of memory types by applying an input signal to the memory system containing the plurality of memory types and detecting differing outputs from the plurality of memory types during a predetermined time period after the input signal is applied. Extended data output (EDO), dynamic random access memories (DRAM) are thereby distinguished from fast page mode (F/P) DRAM. Similarly, nonvolatile memory such as DRAM interface flash memory (DIFM) are distinguished from conventional DRAMs.

Abstract: Disclosed is a nonvolatile memory, compatible with a dynamic random access memory, including a memory array divided into a plurality of blocks, each of the blocks being divided into a plurality of sub-blocks, reading and writing row decoders for selecting rows of the memory array, and reading and writing gate drive circuits for selecting a plurality of drive lines which supply source voltages to the rows of the memory array, wherein the memory array employs a plurality of section decoders which are arranged between the sub-blocks, each of the section decoders being assigned to a half of the rows belong to the sub-block and connecting the drive lines to the rows.

Abstract: A sense amplifier has a pair of output terminals and a first pair of pull-up transistors. A second pair of transistors is connected between the output terminals and a pull-down node. The gate electrodes of the second pair are cross-coupled to the output terminals. A third pair of transistors is connected between the output terminals and the pull-down node and have gate electrodes coupled to input potentials. A fourth pair of transistors is connected between the output terminals and the pull-down node and also have gate electrodes coupled to input potentials.

Abstract: A bit line reference circuit for a nonvolatile semiconductor memory device performs a referenced data access operation using a single bit line having upper and lower portions. The circuit has an open bit line structure and includes an upper memory cell string connected to the upper portion of the bit line, and a lower memory cell string connected to the lower portion of the bit line. An upper reference cell string is connected to the upper bit line for providing a reference potential to the upper bit line in response to a first control signal, while the lower memory cell string is selected. A lower reference cell string is connected to the lower bit line for providing a reference potential to the lower bit line in response to a second control signal, while the upper memory cell string is selected. A page buffer is connected between the upper and lower portions of the bit line and accesses data by comparing the potentials on the upper and lower portions of the bit line.

Abstract: A sense amplifier circuit for a nonvolatile semiconductor memory device, with NAND structured cells, includes a bit line isolation section located between a pair of bit lines connected to a memory cell array and a pair of sub-bit lines connected to an input/output gate circuit, a latch type voltage-controlled current source having n-channel MOS transistors connected to the sub-bit lines, and a switching section connected between the voltage-controlled current source and a signal line. The bit lines are electrically isolated from the sub-bit lines by provision of a bit line isolation section receiving an isolation control signal during the sensing operation. The sense amplifier circuit sensing operation is not affected by bit line load impedance and, accordingly, the sensing speed is improved and peak current is reduced.

Abstract: An electrically erasable and programmable nonvolatile memory device (EEPROM) such as a flash memory, is pin compatible with a dynamic random access memory device (DRAM), such that flash memory may be connected to a DRAM bus. Preferably, the flash memory is read and write timing-compatible with the DRAM read and write signals and is also preferably block read and block write timing compatible with DRAM block read and block write signals. The flash memory accepts signals to perform sleep and erase functions from signal lines of a DRAM bus which are not used by a DRAM. In order to perform a block erase, which is a characteristic of flash memory, the device preferably accepts an instruction to perform a block erase from signal lines of a DRAM bus which are not used by a DRAM and a block address for the block erase from the most significant bit address lines of the DRAM bus.

Abstract: Nonvolatile integrated circuit memory devices, such as EEPROMs, use unselected shared latching sense amplifiers to latch data from memory cells which are to be reprogrammed after a page erase, and to resupply the latch data to the memory cells which are to be programmed after erase, to thereby internally reprogram the latched data into erased memory cells after page programming. Transferring circuits and methods are provided for transferring data between shared latching sense amplifiers to permit internal reprogramming. High speed and simplified reprogramming of EEPROMs is thereby provided.

Abstract: Methods of programming flash EEPROM integrated circuit memory devices containing an array of NAND cells therein include the steps of applying a preselected logic signal to a select transistor of a NAND memory cell to inhibit the likelihood of inadvertent programming thereof when adjacent cells are being programmed. According to one embodiment, a first logic signal having a first non-zero potential (V.sub.fp) is applied to a bit line BL of a first NAND memory cell in the array. Then, at commencement of a first time interval (TI), a second logic signal having a second potential which is greater than the first potential is applied to the gate (SSL) of the first select transistor ST1 to thereby turn-on the first select transistor "hard" and drive the potential of a source (S) thereof towards the potential of the bit line (i.e., V.sub.fp). Here, the first potential V.sub.fp is preferably selected to be higher than the power supply voltage VCC.

Abstract: A nonvolatile memory with NAND structured cells includes a plurality of cell units formed of a plurality of series-connected memory transistors, each having a source, a drain, a floating gate and a control gate. A row decoder is connected to the control gates of each memory transistor selects at east one of the cell units and one of the memory transistors within the selected cell unit. During programming, the row decoder causes a different pass potential to be applied to nonselected word lines adjacent to selected word lines than that which is applied to other nonselected word lines. Adjacent memory transistors respectively connected to the drain and source of the selected memory transistor on an unselected bit line are thus rendered nonconductive. Thereafter, the selected memory transistor is charged to a local boost potential when a programming potential is applied thereto, and a variation of its threshold voltage is prevented.

Abstract: For a SRAM having a sense amplifier amplifying memory data and a read/write control circuit controlling operations of the sense amplifier, a data output buffer circuit is provided, which includes: a drive output node from which data output buffer provides output data; a first circuit providing a NOR function of an SAS signal from the sense amplifier and an output enable signal (OE) from the read/write control circuit; a second circuit providing a NOR function of an SAS signal from the sense amplifier and the output enable signal (OE) from the read/write control circuit; a third circuit eliminating noise produced by transition in the outputs of the first and second circuit and also enhancing a response time; a fourth circuit inverting the output of the first circuit; a fifth circuit inverting twice, sequentially, the output of the second circuit; and a sixth circuit responsive to the fourth and fifth circuit, alternatively providing, depending on the SAS and an SAS signal from the sense amplifier, one of three

Abstract: SRAM device having a power supply voltage control circuit capable of preventing the failure of memory cells used for a long period of time, without lowering a power supply voltage is disclosed. The SRAM device includes a plurality of word lines, a plurality of pairs of bit lines, a plurality of memory cells each coupled between a word line and each pair of bit lines, and a power supply regulating stage coupled to each memory cell, for decreasing a supply voltage delivered to each memory cell when an external power supply voltage exceeds a specified voltage level, and delivering the external power supply voltage to each memory cell when the external power supply voltage does not exceed the specified voltage level. If an external power supply voltage is lower than a voltage level Vc, the supply voltage is supplied as a power source of the memory cell.

Abstract: A CMOS input buffer for converting the TTL level signals to the CMOS level signals, thereby being capable of stably operating within all allowable range of the power supply voltage, is disclosed. Said CMOS input buffer includes an inverter, a reference voltage generating circuit, a power supply voltage tracer circuit and an input circuit. The input circuit includes P-channel MOS transistors and N-channel MOS transistors so as to supply a stable logic output in response to the input signal of TTL level, regardless of variation of the power supply voltage Vcc, under the control of a voltage that is approximately proportional to the difference between the reference voltage and the power supply voltage within a fixed range of the power supply voltage.