Abstract: Circuits and methods are provided for generating clock signals and correcting duty cycle distortion in clock signals. A circuit for generating a clock signal includes a multiplexer circuit and an edge-triggered flip-flop circuit. The multiplexer circuit selectively outputs one of a plurality of input clock signals. The edge-triggered flip-flop detects a transitioning edge of the input clock signal that is selectively output from the multiplexer circuit, and in response to the detection, samples a logic level of a received data signal, and generates a transition of an output clock signal at an output port of the edge-triggered flip-flop. The multiplexer circuit selectively outputs one of the plurality of input clock signals to a clock signal port of the edge-triggered flip-flop, based on a logic level of the output clock signal at the output port of the edge-triggered flip-flop, which is input to a select control port of the multiplexer circuit.

Abstract: Circuits and methods are provided for efficient feed-forward equalization when sample-and-hold circuitry is employed to generate n time-delayed versions of an input data signal to be equalized. To equalize the input data signal, m data signals are input to m feed-forward equalization (FFE) taps of a current-integrating summer circuit, wherein each of the m data signals corresponds to one of the n time-delayed versions of the input data signal. A capacitance is precharged to a precharge level during a reset period of the current-integrating summer circuit. An output current is generated by each of the m FFE taps during an integration period of the current-integrating summer circuit, wherein the output currents from the m FFE taps collectively charge or discharge the capacitance during the integration period. A gating control signal is applied to an FFE tap during the integration period to disable the FFE tap during a portion of the integration period in which the data signal input to the FFE tap is invalid.

Abstract: Dual-loop voltage regulator circuits and methods in which a dual-loop voltage regulation framework is implemented with a first inner loop having a bang-bang voltage regulator to achieve nearly instantaneous response time, and a second outer loop, which is slower in operating speed than the first inner loop, to controllably adjust a trip point of the bang-bang voltage regulator to achieve high DC accuracy.

Abstract: A design for an oscillator, and a PLL incorporating such an oscillator, which takes up little physical area but maintains a large tuning range and low phase noise. Two LC-tanks are nested and switched. Through tuning the inactive tank, the range of the active tank may be increased and finer tuning becomes possible.

Abstract: Methods and apparatus are provided for timing recovery for an input/output bus with link redundancy. A parallel input/output interface receiver includes a plurality of data receivers, each configured to respectively receive input data from a respective one of n+m channels, where n is an integer greater than one and m is an integer greater than or equal to one. The input data is non-calibration data for the n channels and is calibration data for the m channels. The interface receiver further includes a first phase adjustor configured to provide a first clock signal to the plurality of data receivers for sampling of only the non-calibration data at any given time, and a second phase adjustor configured to provide a second clock signal to the plurality of data receivers for sampling of only the calibration data at any given time.

Abstract: In one embodiment, the invention is a hybrid superconducting-magnetic memory cell and array. One embodiment of a memory cell includes a magnetoresistive element and at least one superconducting element wired in parallel with the magnetoresistive element. In a further embodiment, memory cells of the disclosed configuration are arranged to form a memory array.

Abstract: Circuits and methods are provided for efficient feed-forward equalization when sample-and-hold circuitry is employed to generate n time-delayed versions of an input data signal to be equalized. To equalize the input data signal, m data signals are input to m feed-forward equalization (FFE) taps of a current-integrating summer circuit, wherein each of the m data signals corresponds to one of the n time-delayed versions of the input data signal. A capacitance is precharged to a precharge level during a reset period of the current-integrating summer circuit. An output current is generated by each of the m FFE taps during an integration period of the current-integrating summer circuit, wherein the output currents from the m FFE taps collectively charge or discharge the capacitance during the integration period. A gating control signal is applied to an FFE tap during the integration period to disable the FFE tap during a portion of the integration period in which the data signal input to the FFE tap is invalid.

Abstract: Circuits and methods are provided for generating clock signals and correcting duty cycle distortion in clock signals. A circuit for generating a clock signal includes a multiplexer circuit and an edge-triggered flip-flop circuit. The multiplexer circuit selectively outputs one of a plurality of input clock signals. The edge-triggered flip-flop detects a transitioning edge of the input clock signal that is selectively output from the multiplexer circuit, and in response to the detection, samples a logic level of a received data signal, and generates a transition of an output clock signal at an output port of the edge-triggered flip-flop. The multiplexer circuit selectively outputs one of the plurality of input clock signals to a clock signal port of the edge-triggered flip-flop, based on a logic level of the output clock signal at the output port of the edge-triggered flip-flop, which is input to a select control port of the multiplexer circuit.

Abstract: Capacitive level-shifting circuits and methods are provided for adding DC offsets to the output of a current-integrating amplifier. For example, a current-integrating amplifier includes an input amplifier stage and an output offset circuit. The input amplifier stage includes an input node, a first output node, and a first switch connected between the first output node and a power supply node. The output offset circuit is connected to the first output node of the input amplifier stage and to a second output node of the current-integrating amplifier. The output offset circuit includes a first series capacitor coupled between the first output node of the input amplifier stage and the second output node of the current-integrating amplifier. The output offset circuit switchably connects a bias voltage to the second output node and charges the first series capacitor to add a DC offset to the second output node of the current-integrating amplifier.

Abstract: Circuits and methods are provided for generating clock signals and correcting duty cycle distortion in clock signals. A circuit for generating a clock signal includes a multiplexer circuit and an edge-triggered flip-flop circuit. The multiplexer circuit selectively outputs one of a plurality of input clock signals. The edge-triggered flip-flop detects a transitioning edge of the input clock signal that is selectively output from the multiplexer circuit, and in response to the detection, samples a logic level of a received data signal, and generates a transition of an output clock signal at an output port of the edge-triggered flip-flop. The multiplexer circuit selectively outputs one of the plurality of input clock signals to a clock signal port of the edge-triggered flip-flop, based on a logic level of the output clock signal at the output port of the edge-triggered flip-flop, which is input to a select control port of the multiplexer circuit.

Abstract: A parallel data link includes a redundant line. A bank of switches permits any arbitrary line of the link to be enabled or disabled for carrying functional data, each line being dynamically calibrated in turn by disabling the line and allowing other lines to carry the functional data. The switches are located downstream of alignment mechanisms so that data input to the switches is compensated for data skew. Preferably, receiver synchronization circuitry in each line operates in a respective independent clock domain, while the switches and calibration mechanism operate in a common clock domain. Preferably, the receiver synchronization circuits provide an adjustable delay corresponding to a variable number of clock cycles to align the outputs of the receiver synchronization circuits with respect to one another, which can accommodate high data skew.

Abstract: An apparatus comprises an amplifier circuit comprising at least one output node and a common-mode restoration circuit capacitively coupled to the at least one output node of the amplifier circuit. The common-mode restoration circuit is configured to introduce at least one common-mode restoring signal onto the output node, wherein the at least one common-mode restoring signal transitions in correspondence with an operation interval of the amplifier circuit and thereby compensates for a common-mode voltage drop on the at least one output node of the amplifier circuit. In one example, the amplifier circuit may comprise a current-integrating amplifier circuit, and the operation interval may comprise an integration interval.

Abstract: Sense amplifier-type latch circuits are provided which employ static bias currents for enhancing operating frequency. For example, a sense amplifier-type latch circuit includes a latch circuit that captures and stores data during an evaluation phase of the sense amplifier-type latch circuit, and outputs the stored data to differential output nodes. An input differential transistor pair has drains connected to the latch circuit and sources commonly connected to a coupled source node. A static bias current circuit is connected to the coupled source node to provide a static bias current which flows through the differential transistor pair and cross-coupled inverters of the latch during a precharge phase. A switch device, which is connected to the coupled source node, is turned off during the precharge phase and turned on during the evaluation phase by operation of a clock signal to increase current flow through the differential transistor pair.

Abstract: Circuits and methods are provided for efficient feed-forward equalization when sample-and-hold circuitry is employed to generate n time-delayed versions of an input data signal to be equalized. To equalize the input data signal, m data signals are input to m feed-forward equalization (FFE) taps of a current-integrating summer circuit, wherein each of the m data signals corresponds to one of the n time-delayed versions of the input data signal. A capacitance is precharged to a precharge level during a reset period of the current-integrating summer circuit. An output current is generated by each of the m FFE taps during an integration period of the current-integrating summer circuit, wherein the output currents from the m FFE taps collectively charge or discharge the capacitance during the integration period. A gating control signal is applied to an FFE tap during the integration period to disable the FFE tap during a portion of the integration period in which the data signal input to the FFE tap is invalid.

Abstract: Circuits and methods are provided for generating clock signals and correcting duty cycle distortion in clock signals. A circuit for generating a clock signal includes a multiplexer circuit and an edge-triggered flip-flop circuit. The multiplexer circuit selectively outputs one of a plurality of input clock signals. The edge-triggered flip-flop detects a transitioning edge of the input clock signal that is selectively output from the multiplexer circuit, and in response to the detection, samples a logic level of a received data signal, and generates a transition of an output clock signal at an output port of the edge-triggered flip-flop. The multiplexer circuit selectively outputs one of the plurality of input clock signals to a clock signal port of the edge-triggered flip-flop, based on a logic level of the output clock signal at the output port of the edge-triggered flip-flop, which is input to a select control port of the multiplexer circuit.

Abstract: In one embodiment, the invention is a hybrid superconducting-magnetic memory cell and array. One embodiment of a memory cell includes a magnetoresistive element and at least one superconducting element wired in parallel with the magnetoresistive element. In a further embodiment, memory cells of the disclosed configuration are arranged to form a memory array.

Abstract: A 1/n-rate decision feedback equalizer (DFE) and method include a plurality of branches. Each branch includes a summer circuit configured to add a feedback signal to a received input, and a latch configured to receive an output of the summer circuit in accordance with a clock signal. A feedback circuit includes a multiplexer configured to receive as input, an output of each branch, the multiplexer having a clocked select input and configured to multiplex the output of each branch to assemble a full rate bit sequence, and a filter configured to provide cancellation of intersymbol interference (ISI) from the received input to be provided to the summer circuit of each branch.

Abstract: A phase interpolator circuit is provided that generates an output clock signal by interpolating between phases of first and second clock signals. Interpolation is performed by detecting an edge of the first clock signal and applying a first current to charge a capacitance of an output node to a voltage level which is less than or equal to a switching threshold of a voltage comparator, and detecting an edge of the second clock signal and applying a second current to charge the capacitance of the output node to a voltage level which exceeds the switching threshold of the voltage comparator. The magnitude of the first current is varied to adjust a timing at which the capacitance of the output node is charged to a voltage level that exceeds the switching threshold of the voltage comparator and to adjust a phase of the output clock signal output from the voltage comparator.

Abstract: A phase interpolator circuit is provided that generates an output clock signal by interpolating between phases of first and second clock signals. Interpolation is performed by detecting an edge of the first clock signal and applying a first current to charge a capacitance of an output node to a voltage level which is less than or equal to a switching threshold of a voltage comparator, and detecting an edge of the second clock signal and applying a second current to charge the capacitance of the output node to a voltage level which exceeds the switching threshold of the voltage comparator. The magnitude of the first current is varied to adjust a timing at which the capacitance of the output node is charged to a voltage level that exceeds the switching threshold of the voltage comparator and to adjust a phase of the output clock signal output from the voltage comparator.

Abstract: Analog peaking amplifiers with enhanced peaking capability are provided. For example, a peaking amplifier circuit includes an input node, output node, a feedback node, a first input amplifier having an input connected to the input node and an output connected to the feedback node, a second input amplifier having an input connected to the input node, a coupling capacitor connected between an output of the second input amplifier and the feedback node, a forward-path gain amplifier having an input connected to the feedback node and an output connected to the output node, and a feedback circuit having an input coupled to the output node and an output connected to the feedback node. A peaking response of the peaking amplifier circuit is realized by capacitively coupling the output of the second input amplifier to the feedback node to suppress negative feedback and increase the peaking gain at higher frequencies.