Abstract: A voltage generator for low power applications includes a circuit for generating, controlling and maintaining a high voltage for low power applications in an integrated circuit. The circuit includes separate standby and active circuits for pumping V.sub.CCP of a DRAM under different circumstances. The standby and active circuits operate independently of one another, but may operate simultaneously, to pump charge to V.sub.CCP. The standby circuit is generally a low power circuit activated in response to power up and leakage current conditions to maintain V.sub.CCP. The active circuit is generally a larger circuit and can pump more current. The active circuit is generally responsive to the word lines being driven. Accordingly, the voltage generator can maintain V.sub.CCP while minimizing power consumption in DRAM.

Abstract: A method and apparatus for generating two control signals (LPB and LNB) to activate local sense amplifier driver transistors is described. The rise and fall times of these signals as well as their levels keep the sense speed and peak currents as constant as possible over the specified voltage and temperature ranges. This is achieved preferably by using current sources based on resistors to control the rise/fall times and current mirrors or modeling circuits to set the voltage levels. Preferably circuitry is provided to determine when LNB and LPB reach intermediate and full voltage levels. The timing is set to spread out the current peak into three separate smaller peaks.

Abstract: A row decoder that includes circuitry to provide a self-timed bootstrap signal. The self-timed bootstrap signal is generated in response to the selection of the row decoder. At the same time, a capacitive device is charged in order to bootstrap a word line. The self-timed bootstrap signal causes a clock generator circuit to output a clock signal that will be used to bootstrap the word line. The self-timed bootstrap signal may be generated by other row decoders. The generation of the self-timed bootstrap signal by a row decoder is responsive to any variations in that decoder, thus always providing an accurate and precise timing of the clock signal to be used for the bootstrapping.

Abstract: A fast low-to-high voltage translator with immunity to latch-up. The circuit includes a voltage comparator and employs at least one transistor which is used to quickly pull up a node. If further uses another transistor which is capable of limiting the voltage at certain nodes in order to eliminate latch-up if a pumped power supply is provided to the circuit. Latch-up therefore is eliminated during power-up. Other transistors are utilized as voltage drop limiters to limit the voltage drop across other transistors during switching. This provides improved reliability by reducing substrate current and hot carriers.

Abstract: A reference voltage generator which compensates for temperature and V.sub.CC variations includes a constant current source and a MOS P-channel transistor. The constant current source provides a constant current over a wide range of V.sub.CC that corresponds to biasing a p-channel transistor in a region where its resistance is constant. The output of the current source is supplied to the P-channel transistor, which is in saturation. The constant current provides a constant voltage drop across the P-channel transistor. Hence, a stable reference voltage is generated. Temperature compensation is provided by biasing the P-channel transistor to saturation and supplying a constant current that the corresponds to biasing a p-channel transistor where the resistance is substantially constant over a temperature range. The current causes a voltage drop across the P-channel transistor to maintain a stable reference voltage.

Abstract: A DRAM is operated based upon an external clock input, a column enable, and a row enable. The DRAM is accessed and row and column addresses are latched into buffers based upon the clock input.

Abstract: Column circuitry for a CMOS static RAM includes a bit line clamp combined with a bit line current source regulated by a voltage reference which tracks changes in transistor characteristics. Separate data read and data write lines are provided, with a differential amplifier for each pair of bit lines. The data read lines are coupled to compensated current source loads, and the differential amplifiers are coupled to switching transistors which are also compensated for transistor characteristic changes. Each bit line pair has a sneak capacitance prevention transistor so that in non-selected columns the bit line pairs are coupled together allowing the memory cells therein to pull down all of the bit lines. This isolates the read lines from unwanted capacitance in the differential amplifiers of each of the non-selected columns. Further, a VCC protection circuit is provided.

Abstract: To locate soft cells in a memory cell array, a known logic pattern is written in the memory array. The word lines for the array are then sequentially subjected to a nonstandard test signal such as a slowly varying voltage. Word lines are returned to VCC and the array is then interrogated to identify memory cells which have flipped logic states. These cells are identified as soft or potentially defective cells. The process can be repeated with the logically opposite logic pattern being initially stored in the array. Apparatus is provided for implementing this process on a standard RAM memory cell array. An access pad is added for receipt of an externally generated test signal. A control circuit selectively couples the test signal to the word lines for the memory array.

Abstract: An improved row decoding technique for use in a static RAM. Three stages of row decoders are utilized to further decode partially decoded row address signals and combine the decoded signals with a column address signal to enable selected rows of the memory array. To optimize decoding speed, each stage comprises gates which receive only two inputs from the prior stage and the stages are arranged to allow for sharing of signals between adjacent decoders.

Abstract: A low power I/O scheme is described which is particularly useful in wide word semiconductor memories which include redundant memory cells as well as regular memory cells. In the present scheme, conventional load transistors for a main data bus are turned off during all write operations to conserve power. In addition, predata lines which carry data between memory cells and the main data buss include load transistors that are turned off during normal read or write operations to conserve additional power, and turned on during spare read or write operations to preserve the stability of unselected regular cells. The predata lines are also preferably held above ground potential during read or write operations to prevent conduction of deselected column select transistors.

Abstract: A bootstrap driver circuit is used asynchronously in a static RAM. A capacitor is coupled between second and third nodes, and a charge pump is coupled to provide charge to the second node. Address bits can be applied to the gates of respective transistors whose drains form a common node coupled to the source of a low impedance transistor whose drain is coupled to a first node. An inverter is coupled to the common node for applying a delayed input signal to the gates of first and second enhancement mode transistors. This provides a discharge path for the third node in response to a low level memory address signal thereby to maintain a differential voltage across the bootstrap capacitor. Also disclosed is an input protection circuit when the bootstrap driver is used as a chip select buffer. A timing circuit receives an input signal and develops a first signal and a delayed signal, both of which are applied to the bootstrap driver.

Abstract: A bootstrap driver circuit is used asynchronously in a static RAM. A capacitor is coupled between second and third nodes, and a charge pump is coupled to provide charge to the second node. Address bits can be applied to the gates of respective transistors whose drains form a common node coupled to the source of a low impedance transistor whose drain is coupled to a first node. An inverter is coupled to the common node for applying a delayed input signal to the gates of first and second enhancement mode transistors. This provides a discharge path for the third node in response to a low level memory address signal thereby to maintain a differential voltage across the bootstrap capacitor. Also disclosed is an input protection circuit when the bootstrap driver is used as a chip select buffer. A timing circuit receives an input signal and develops a first signal and a delayed signal, both of which are applied to the bootstrap driver.

Abstract: A circuit is described for precharging and equilibrating the bit lines in a semiconductor memory. The circuit includes a pair of precharging transistors, each coupled between its own bit line and a common node, and each adapted to receive a precharging pulse at its gate. A transistor circuit is coupled to the common node to establish thereat a variable operating potential such that when the precharging pulse occurs, one of the precharging transistors conducts to raise its bit line to a precharge potential while simultaneously reducing the operating potential at the common node. The lower voltage at the common node permits the other precharging transistor to conduct so that its bit line is precharged and both bit lines are equilibrated through the conducting transistors.

Abstract: A single polycrystalline silicon configuration for a memory cell in a static MOS RAM and a method of fabricating the same are described. Three conductivity regions are utilized to form each memory cell. A first conductivity region is formed in the substrate to create a buried ground line and sources and drains of transistors. A second conductivity region is formed within an insulation layer and above the first conductivity region to create a word line, gate regions of the transistors, load resistors, and a power supply line. The power supply line is oriented directly above and parallel to the ground line. A third conductivity region is formed on the surface of the insulation layer to create data lines. The number of process steps and the size of the memory cell are reduced by this configuration.

Abstract: A single polycrystalline silicone configuration for a memory cell in a static MOS RAM and a method of fabricating the same are described. Three conductivity regions are utilized to form each memory cell. A first conductivity region is formed in the substrate to create a buried ground line and sources and drains of transistors. A second conductivity region is formed within an insulation layer and above the first conductivity region to create a word line, gate regions of the transistors, load resistors, and a power supply line. The power supply line is oriented directly above and parallel to the ground line. A third conductivity region is formed on the surface of the insulation layer to create data lines. The number of process steps and the size of the memory cell are reduced by this configuration.

Abstract: A redundancy system is described for a high speed, wide-word semiconductor memory having first and second arrays of regular memory cells. The system includes a plurality of spare columns of cells, half of which are located adjacent the first array and half of which are located adjacent the second array. The number of spare columns which are adjacent each array is equal to the number of regular columns which are simultaneously selectable by an address input. Circuitry is included for responding to an incoming address representative of a defective regular cell for selecting half the spare columns in the first array in lieu of the regular addressed columns therein, and for selecting half the spare columns in the second array in lieu of the addressed regular columns therein.

Abstract: A static RAM (random access memory) is described wherein fully asynchronous active equilibration and precharging of the RAM's bit lines provides improved memory access time and lower active power dissipation. In the preferred embodiment, each change in the memory's row address is sensed for developing a clock pulse of a controlled duration. The clock pulse is received by a group of equilibrating transistors and a group of precharging transistors which are coupled to the memory's bit lines. When the clock pulse occurs, all the abovementioned transistors conduct to effect simultaneous equilibration and pre-charging of the bit lines.

Abstract: A redundancy scheme is described for use with an MOS memory having a main array of memory cells, and a plurality of spare memory cells. Typically, each memory cell is tested for operability by a conventional probe test. When a defective memory cell is found, an on-chip address controller responds to the probe test finding a defective cell by permanently storing and rendering continuously available a fully asynchronous electrical indication of the address of the defective cell. The address controller compares its stored data with memory cell information received during normal memory operation, and generates a control signal indicative of the receipt of an address which corresponds to a defective cell. A spare cell selector responds to the control signal by electrically accessing a spare memory cell and by prohibiting access of the defective memory cell.

Abstract: A substrate bias generator for an integrated circuit, metal-oxide-semiconductor (MOS) random access memory (RAM) is described. The on-chip generator includes two input terminals for receiving first and second trains of periodic pulses. The periodic pulses have the same frequency and are phase synchronized. However, the first train of pulses has a greater duty cycle than the second train of pulses. Amplitude transitions associated with the first and second trains of pulses are capacitively coupled to first and second nodes, respectively. A pair of transistors are coupled to the nodes, one transistor for clamping the first node to ground when the second node receives a positive-going voltage transition, and another transistor for selectively coupling amplitude transitions from the first node to the second node. In operation, both nodes are driven more negative with each successive incoming pulse until they reach about -5 volts for the case in which the amplitude of the incoming pulses is 5 volts.