Abstract: A static random access memory having a static random access memory cell array, row address buffers for receiving row address signals, and column address buffers for receiving column address signals. The static random access memory also includes a clock chain circuit connected to the row address buffers and column address buffers such as to be responsive to transitions in the row address signals and column address signals by generating clock signals for accessing the static random access memory cell array. A method for accessing a static random access memory comprising detecting a transition occurring in a row address signal for addressing a static random access memory cell array; generating a plurality of clock signals in response to the transition in the row address signal; and accessing the static random access memory cell array.

Abstract: This invention relates to a digital circuit for controlling the power usage of an electronic device such as a read only memory (ROM) for a computer device, particularly a portable computer device that relies on a battery power source. The circuit includes the latch, a positive edge detecting circuit, a negative edge detecting circuit, a guaranteed reset circuit, and a delay circuit. Control signals from the device open and close the latch when either a rising or falling edge of these control signals is detected by the edge detecting circuits. The latch itself includes a three input NAND gate and a two input NAND gate. The guaranteed reset circuit ensures that the circuit is initiated. The delay circuit includes a series of inverters and loads. The edge detecting circuits generate a pulse when a rising or falling edge is detected, and include a pulse generating portion, a NAND gate and inverters.

Abstract: A read only memory including: a plurality of memory cells arranged in x rows and y columns in an array; x wordlines each connected to y memory cells in a respective row; y bitlines each associated with x memory cells in a respective column; m reference bitlines each corresponding to n bitlines, each of the reference bitlines having x reference cells each connected to a respective wordline; and m sense amplifiers each having a first input terminal connected to a respective n bitlines and having a second input terminal connected to one of the reference bitlines, and each being responsive to a difference between a signal on one of the n bitlines and a signal on one of the reference bitlines.

Abstract: A row identification circuit identifies which redundant-row fuse has been blown in a memory integrated-circuit by electrically interrogating the integrated-circuit using a switching circuit internal to the memory integrated-circuit. N data output terminals of the memory integrated circuit provide an n-bit binary-coded word which identifies a defective row. To bring out the binary fuse data, the chip is put into a test mode with a TESTF signal which shuts off a normal CMOS transmission gate as well as a latch feedback transmission gate and which turns on another CMOS transmission gate to pass a defective row address bit FUSEB to a data output terminal for the memory device. A switching circuit selectively switches either a defective row address bit TESTB or a data input signal DIN to a data output terminal of the memory integrated circuit. The switching circuit is selectively controlled by a test mode control signal TESTF.

Abstract: A control circuit initiates operation of the ROM array and the RAM array in an ATD circuit includes an EXCLUSIVE NOR circuit having: a RAM SELECT input terminal for receiving a RAM SELECT (RAMCS*) signal, a ROM SELECT input terminal for receiving a ROM SELECT (ROMCS*) signal, and having a chip enable output terminal at which is provided a chip enable signal (CE) at an active LOW state whenever the RAMCS* and the ROMCS* are both the same logic level, both either HIGH or LOW. The control circuit further includes a compensating pulse circuit to compensate for operation of the EXCLUSIVE NOR circuit during a dead-time interval in which the EXCLUSIVE NOR circuit does not function when the RAMCS* and the RAMCS* both change during that dead-time interval. The compensating circuit includes a two pulse generators, each generating an output pulse having a pulse width which is greater than the dead-time interval of the EXCLUSIVE NOR circuit.

Abstract: A resettable latch circuit provides a modified address transition detection (XATD) signal in response to receiving an address-change input pulse signal at a SET input terminal thereof. A RESET input terminal for the latch circuit receives a delayed reset signal from a resettable delay circuit which has its input terminal coupled to the output terminal of the resettable latch circuit to receive the XATD signal. The resettable delay circuit includes a reset control signal terminal to which is coupled an inverted address-change input pulse. One embodiment of the resettable delay circuit includes a series of inverters and MOSFET load resistors as well as shunt MOSFET transistors turned on by the address-change signal to shunt the output terminals of the inverters and reset the delay line. The SET input terminal of the latch circuit also receives a chip-select-change signal pulse which is similar to the address-change pulse.

Abstract: A circuit for connecting a memory cell matrix to voltage sources includes a voltage sensor responsive to the voltage levels of a first voltage source and of a second voltage source by producing a sense signal, and a voltage source coupler connected between the memory cell matrix and the voltage sensor. When the first voltage source voltage level is greater than a predetermined threshold voltage level, the sense signal causes the voltage source coupler to drive the first voltage source voltage level into the memory cell matrix. When the first voltage source voltage level falls to the threshold voltage level, the sense signal also causes the voltage source coupler to drive the second voltage source voltage level into the memory cell matrix to sustain memory cell data.

Abstract: A high-speed current-sensing amplifier using process-insensitive matching of devices to determine the state of a bistable SRAM cell. The benefits include small voltage swings on heavily capacitively loaded bit lines and bit line bars during memory sensing, thereby maximizing the speed of the SRAM device. One embodiment uses a negative feedback amplifier minimize the bit line and bit line bar voltage swings while sensing current through matched PMOS transistors. Another embodiment uses cascoded PMOS devices to limit the swing of the bit lines and bit line bars, and a supply voltage and process-compensated voltage reference source to set the common-mode voltage of matched resistive sense elements. In all cases power on and off circuitry minimize the power of the memory device.