Abstract: A bus interface system and method includes a driver circuit and a receiver circuit coupled on opposite ends of a conducting line of a bus. The driver circuit drives an adjustable current through the conducting line to the receiver circuit. The current level of the adjustable current can be adjusted to one of several levels according to the data item being transferred across the line. The receiver circuit receives the adjustable current and detects the level of the current to identify the information encoded by the signal being transferred. The current level can be set to one of several values such that the information being transferred by the signal can be in one of several possible states. The system therefore is capable of encoding more data than binary systems. Higher data bus transfer rates can therefore be realized.

Abstract: An internal power supply generating circuit for a semiconductor memory device reduces fluctuations in the external power supply by reducing the rate at which a drive transistor is turned on and off. The circuit includes a drive transistor that generates an internal power signal by reducing the external power supply voltage responsive to a bias signal. A feedback loop generates the bias signal and slows down the rate at which the bias signal changes, thereby reducing the rate at which the drive transistor turns on and off. The feedback loop includes a comparator for comparing the internal power supply voltage to a reference voltage and a bias circuit having a pair of push-pull transistors for generating the bias signal responsive to the output of the comparator. To slow down the rate at which the bias signal changes, the bias circuit includes a resistor coupled in series with the transistors and/or a capacitor couple to the output terminal of the bias circuit.

Abstract: A novel parallel bit test circuit is provided to test a semiconductor memory device which comprises a number of memory cell arrays each having a plurality of memory cells, a word line provided in each memory cell array to commonly connect with the plurality of memory cells, and a plurality of I/O (input/output) lines respectively connected with the plurality of memory cells of each memory cell array. The parallel bit test circuit for testing the plurality of memory cells in parallel bits comprises a comparator for comparing the data of the memory cells with an externally input data to produce a test signal applied to a data I/O terminal.

Abstract: A test control circuit and method of testing a memory cell in a semiconductor memory device. The test control circuit includes a memory cell array having a plurality of normal memory cells to store data on a semiconductor substrate and a plurality of redundancy memory cells to substitute for defective normal memory cells. Row and column redundancy fuse boxes include fuse elements to be electrically fused to enable row and column redundancy decoders for selecting rows and columns of the redundancy memory cells. A redundancy cell test signal generator generates, in response to a test signal applied to an extra line in the address bus, a master clock for testing the redundancy memory cell under the same mode as a test mode of the normal memory cell. A test controller provides an enable signal for selecting the redundancy memory cells of a memory array in response to logic levels of the master clock and an address signal applied during the redundancy memory cell test.

Abstract: An active power supply voltage boosting circuit for a semiconductor memory device according to the present invention causes operation of the active cycle boosted voltage generating circuit to elevate the level of the boosted power supply voltage V.sub.PP when the detected level of the boosted power supply voltage V.sub.PP is lower than a target voltage level. Thus, the boosted power supply voltage V.sub.PP can be stably maintained to the target voltage level. When the boosted power supply voltage V.sub.PP becomes higher than the target voltage level, generation of the boosted power supply voltage V.sub.PP is stopped, and as a result, unwanted consumption of the electrical current and also the damage to the semiconductor memory device by high voltage can be prevented.

Abstract: A defective cell repairing circuit for repairing a defective cell in a packaged semiconductor memory device enables repair mode operations for mapping an address of a detected defective cell to a redundant cell. The address of the defective cell is programmed by selectively cutting fuses corresponding to each bit of the defective cell address. The defective cell address programming operation uses input terminals on the packaged semiconductor memory device which are used for address signals in a normal operation mode, so that no additional pins are required. Repair mode operations are prevented after the repair mode is completed. Thereafter, an external address supplied to the semiconductor memory device is compared with the programmed defective cell address determined by the state of the fuses, and a redundant cell is selected if the two addresses correspond.

Abstract: A wafer burn-in test circuit for sensing a defective cell of a semiconductor memory device having a plurality of memory cells connected to a word line and a row decoder for selecting the word line. The burn-in test includes a word line driver circuit having an input coupled to a row decoding signal generated by the row decoder, and an ouput coupled to the word line, a control circuit having a first input coupled to a burn-in voltage signal, and a second input coupled to a control signal, and an electrical line connected between the word line driver circuit and the control circuit. In a normal mode of operation, the word line driver circuit is responsive to the row decoding signal for raising the word line to an enable voltage level. In a burn-in test mode of operation, the control circuit is responsive to the control signal for applying a burn-in voltage to the word line via the electrical line and the word line driver circuit.

Abstract: A semiconductor memory device using a low level supply voltage has separation gates for isolating adjacent bit lines. The device may be constructed with a circuit for receiving a high voltage supplied by a high voltage generator resident upon the chip so as to provide the separation gates with a voltage increased at least by the amount of the threshold voltage of the separation gates over the supply voltage.

Abstract: A semiconductor memory device has adjacent memory arrays and isolation transistors disposed between a common bit sense amplifier and the memory arrays. An isolation control circuit according the present invention generates the power supply voltage Vcc (not the boost voltage Vpp) during the burn-in mode of operation, so that the gate oxide layer of the isolation transistors is prevented from being destroyed or deteriorated.

Abstract: A high density semiconductor device is provided with an improved voltage pumping (bootstrapping) circuit. The voltage pumping circuit generates at an initial power-up state a first output voltage which is substantially identical to the memory device source supply voltage. The pumping circuit then pumps the first output voltage up to a second output voltage which is higher than the first output voltage. The pumping operation is achieved prior to or upon the semiconductor memory device being enabled in response to a series of pulses output from an oscillator.

Abstract: A semiconductor memory device divided into a number of main blocks each main block having a number of subblocks selects a single main block and enables the subblocks of the selected main block, so as to reduce the power consumptions. The semiconductor memory device includes a block selector for selecting one of the main blocks in response to row address signals, a number of first boost circuits for selecting the subblocks of the selected main block in response to the row address signals, and a number of second boost circuits adapted to be disabled in response to the row address signals.

Abstract: A column redundancy circuit for a semiconductor memory device, e.g., a DRAM, which includes a normal memory array comprised of a plurality of memory blocks each comprised of a matrix of rows and columns of memory cells, with at least two of the memory blocks sharing common columns, and with at least one of the columns being defective, in the sense of being connected to at least one memory cell which has been determined to be defective.

Abstract: An arrangement of a word line driver stage for semiconductor memory device is disclosed. The present invention is characterized in that a word line driver stages are into several sub-stages WD11-WD51 within a memory cell array, and each word line extending from a first one or a second one of the sub-stages is alternatively coupled to the sub-stage adjacent thereto. Thus this arrangement is capable of reducing the signal transmission delay and eliminating the adverse factor in the current critical design rule and layout.

Abstract: A semiconductor memory device for minimizing the resistance attendant on reaching as far as each sense amplifier connected to a memory cell. A first plurality of power supply lines are alternatively disposed between column select lines which is formed over a plurality of lines of semiconductor memory device in a column direction. The first plurality of power supply lines the first plurality of ground lines are connected to a second plurality of power supply lines and a second plurality of ground lines which are disposed under the column select lines in a row direction, to thereby provide a netlike power supply structure. Consequently, the operating speed of a chip is improved by minimizing the resistance attendant on reaching as far as the sense amplifiers connected to each memory cell and the efficiency of the semiconductor memory device is greatly promoted by suppressing a coupling phenomenon caused between the column select lines.

Abstract: Disclosed is a data transmission circuit with a higher data access time and allowing for higher chip density, used for a semiconductor memory device. A pre-amplifier connects segmented I/O lines with data I/O lines, amplifies weak voltage from the bit lines and is mounted on the strapping area of the chip so as to secure the high chip density.

Abstract: There is disclosed a redundant device for a semiconductor memory device comprising a plurality of normal cell arrays each having sense amplifier comprising an isolation gate for isolating or connecting the bit lines between adjacent ones of the normal cell arrays in response to isolation signal, a redundant cell array connected only with one of the adjacent redundant cell arrays, a control signal generating device for generating the isolation signal and a sensing signal to control the sense amplifiers respectively corresponding with the normal cell array connected with the redundant cell array and the normal cell array not connected with the redundant cell array, and device for generating a redundant control signal in response to a defect of an externally inputted address signal and a signal to select a word line of the redundant cell array.

Abstract: A semiconductor integrated circuit chip has an identification circuit connected between a power voltage supply terminal and one of the input terminals of the chip. The identification circuity includes a voltage limiter to limit the input potential difference between the power voltage supply terminal and the input terminal to a predetermined voltage level. The identification circuit further includes an option device connected to the voltage limiter to provide identification information of the chip. According to the identification circuit, chip identification testing may be achieved with existing input/output and power supply terminals, thereby eliminating the need for extra test and diagnosis pins or additional identification equipment employed during testing.