Cypress Semiconductor Corporation

Simon J Lovett

Cathal G Phelan

Ashish Pancholy

Mathew R Arcoleo

An input buffer having a stable trip point over at least process skew and supply voltage variations includes a first inverter stage; a second inverter stage; and an arrangement for compensating for process skew and supply voltage variations. The compensating arrangement is disposed both in the pull-up and pull-down paths, and increases the conductivity of the pull-up path and decreases the conductivity of the pull-down path when the DC trip point of the input buffer falls below nominal. The compensating arrangement also decreases the conductivity of the pull-up path and increases the conductivity of the pull-down path when the DC trip point rises above nominal. The compensating arrangement may include at least one device disposed in each of the pull-up and pull-down paths. The conductivity of these devices may then be controlled by a reference signal that swings about the DC trip point responsive to at least process skew corners and variations in supply voltage. Alternatively, the compensating arrangement may include a first and a second pair of devices of a first and second conductivity type connected in parallel and disposed in the pull-up and pull-down paths. The devices of the first conductivity type are connected at their control electrodes to the supply voltage and the devices of the second conductivity type are connected, at their control electrodes, to ground. The DC trip point is then stabilized at about nominal over at least process skew and variations in supply voltage.

Buffer with stable trip point

A random access memory with a read port, a write port, a read/write control signal configured to control data transfer operations at the read port and/or the write port on both rising and falling transitions, and a first random access memory array configured to store and/or retrieve data at a first random address in the first random access memory array defined by one or more signals on a write address bus and/or a read address bus. One preferred embodiment further includes a write data register storing or latching data in response to a first transition of the read/write control signal, and the array storing data in response to a second transition of the read/write control signal. Other preferred embodiments further include an n&middot;m-bits-wide input data bus coupling a set of data inputs to the write data register, and/or an n&middot;m-bits-wide output data bus coupling the read data register to a set of data outputs, where n and m are each independently an integer >2.

Random access memory having independent read port and write port and process for writing to and reading from the same

A random access memory with a data input bus, a data output bus, a random access memory array configured to transfer data to random write addresses and from random read addresses in the random access memory array, an address bus providing the random read addresses and the random write addresses, and a first periodic signal configured to control data transfer operations (i) to the random access memory array in response to a first transition of the periodic signal and (ii) from the random access memory array in response to a second transition of the periodic signal, wherein the second transition of the periodic signal is complementary to the first transition of the periodic signal. One preferred embodiment further includes circuitry operable to write data into and read data from the random access memory array. Other preferred embodiments further include a write data register and/or a read data register. In a further embodiment, each of the data input bus and the data output bus is unidirectional. The invention also concerns a process for reading data from and writing data to a random access memory array.

Random access memory having a read/write address bus and process for writing to and reading from the same

A circuit including an address bus providing random addresses for a random access memory array, and a register configured to receive, store or transfer (i) a first random address from the address bus in response to a first periodic signal transition and (ii) a second random address from the address bus in response to a second periodic signal transition, wherein the first and second periodic signal transitions occur within a single periodic signal cycle, and are preferably complementary to each other. In a further embodiment, the invention concerns a random access memory having an address bus providing random address information for a random access memory array, a predecoder configured to at least partially decode the random address information from the address bus, a register configured to receive, store or transfer (i) a first at least partially decoded random address from the address bus in response to a first periodic signal transition and (ii) a second at least partially decoded random address from the address bus in response to a second periodic signal transition, wherein the first and second periodic signal transitions occur within a single periodic signal cycle; and a postdecoder configured to activate the random addresses in the random access memory in response to receiving the random addresses from the register.

Circuit and method for implementing single-cycle read/write operation(s), and random access memory including the circuit and/or practicing the method

Synchronous random access memory having a read/write address bus and process for writing to and reading from the same

A circuit comprising a first and a second sense transistor, a bitline and a complementary bitline, one or more first switches and one or more second switches. The first switches may be configured to couple the first sense transistor to the bitline and the second sense transistor to the complementary bitline. The second switches may be configured to couple the first sense transistor to the complementary bitline and the second sense transistor to the bitline. The first and second switches may be configured to provide voltage threshold matching between the first and second transistors.

Threshold voltage mismatch compensated sense amplifier for SRAM memory arrays

A nonvolatile cell comprising a first device comprising a first transistor type and a second device comprising a second transistor type. The first device may have a gate, a source, a drain and a gate oxide layer over the gate. The second device may have a gate, a source, a drain and a floating gate formed between the gate of said first device and the gate of the second device. The floating gate may be configured to store a charge in response to (i) a first voltage applied to the source and drain of said first device and (ii) a second voltage applied to the source and drain of the second device.

Nonvolatile cell

A NOR gate including a pull-down circuit coupled to a pull-up circuit. The NOR gate is configured to drive an output signal to a low logic state at a substantially uniform slew rate regardless of the number of input signals that are in high logic state. The pull-down circuit may include a first plurality of transistor circuits each coupled to a corresponding one of the plurality of input signals, and a second plurality of transistor circuits each comprising a plurality of transistors coupled in parallel with each other and coupled to a corresponding one of the plurality of input signals or a complement of a corresponding one of the plurality of input signals. The first and second plurality of transistor circuits may each include an n-channel MOS (NMOS) transistor. The NOR gate may be incorporated into a decoder of a synchronous or asynchronous input path circuit to generally reduce the set-up and hold time window of the input path circuit.

Symmetrical NOR gates

Circuit and method for implementing single-cycle read/write

A NAND gate including a pull-down circuit coupled to a pull-up circuit. The NAND gate is configured to drive an output signal to a high logic state at a substantially uniform slew rate regardless of the number of input signals that are in a low logic state. The pull-up circuit may include a plurality of load circuits each coupled to a corresponding one of the plurality of input signals, and a plurality of transistor circuits each comprising a plurality of transistors coupled in parallel with each other and coupled to a corresponding one of the plurality of input signals or a complement of a corresponding one of the plurality of input signals. The plurality of load circuits and the plurality of transistors may each include a p-channel MOS (PMOS) transistor. The NAND gate may be incorporated into a decoder of a synchronous or asynchronous input path circuit to generally reduce the setup and hold time window of the input path circuit.

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Milpitas, CA, United States of America

Simon J Lovett