Xilinx, Inc.

Declan Carey

Ronan Sean Casey

Hongtao Zhang

Kevin Zheng

Pedro W Neto

Catherine Hearne

James Hudner

Kevin Geary

Lokesh Rajendran

Thomas Mallard

Brendan Farley

Mohamed N Elzeftawi

Darragh Walsh

Ivan Bogue

Frantz Stephane Florent Ngankem Ngankem

Marc Erett

Mark Smyth

Methods, systems, and apparatus described herein make a multi-level PAM signal (PAM-N signal) at a transmitter using CMOS-based components. By forming the PAM-N signal at the transmitter, receivers do not have to recombine and/or realign multiple signals and only employs a single transmission line channel (or two transmission line channels in differential implementations) to convey the data stream to the receiver from the transmitter.

Ultra-high-speed PAM-N CMOS inverter serial link

Apparatus and associated methods relate to a time-interleaved integrating sampling front-end circuit using integrating buffers. In an illustrative example, a circuit may include N sampling layers of circuits, an isampling layer of circuits of the N sampling layers of circuits may include: (a) Xbuffers configured to receive an analog signal, X&#x2265;1, and, (b) Ytrack-and-hold circuits, each track-and-hold circuit of the Ytrack-and-hold circuits is coupled to an output of a corresponding buffer of the X buffers, Y&#x2265;1, at least one buffer of the Xbuffers may include an integrating buffer, N&#x2265;i&#x2265;1. By implementing integrating buffers, a faster linear type of step settling response may be obtained as opposed to a slower exponential type of settling response.

Low power device for high-speed time-interleaved sampling

Apparatus and associated methods relate to providing a regulation loop using a digital representation of a loop error signal along with a flexible multiplying capacitive digital-to-analog converter (MC-DAC) circuit to control one or more power switches (e.g., transistors) delivering required power (including voltage and/or current) to a load circuit. In an illustrative example, the MC-DAC circuit may include a digital-to-analog converter (DAC) configured to selectively couple to two different reference voltages in response to switch control signals generated by a digital filter. A capacitive level shifter may be coupled to the output of the DAC. A re-sampling circuit may be coupled to the output of the capacitive level shifter to generate a gate control signal to control the one or more power switches. The regulation loop may advantageously generate the gate control signal using a substantially reduced die area.

Hybrid multiplying capacitive digital-to-analog converter (MC-DAC) based loop regulation

A frequency divider circuit includes an oscillator comprising a plurality of delay elements coupled in series with each other, a first coupling circuit coupled to a first oscillator node and including a control terminal to receive a first retiming signal, and a first multiplexer including inputs coupled to receive the input signal and a complementary input signal, a control terminal coupled to a second oscillator node, and an output to provide the first retiming signal. The first multiplexer may be configured to alternate between injecting the input signal into the first oscillator node based on rising edges of the input signal and injecting the input signal into the first oscillator node based on falling edges of the input signal in response to a logic state of an oscillation waveform appearing at the second oscillator node.

Inductor-less divide-by-3 injection locked frequency divider

This disclosure relates generally to continuous time linear equalization. In an example of a continuous time linear equalizer, a variable gain circuit includes transistors having gate nodes respectively as a first and a second input node. A first transimpedance circuit is connected between the first input node and a first output node. A second transimpedance circuit is connected between the second input node and a second output node. A source node of each of the first transistor and the second transistor are commonly connected to one another. In the same or another equalizer, output nodes of a first frequency peaking circuit are connected to input nodes of a second frequency peaking circuit. In such a same or another equalizer, an RC feedback circuit has tap-off nodes and summing nodes respectively connected at the output nodes of the first frequency peaking circuit.

Continuous time linear equalization

A circuit for implementing a differential input receiver is described. The circuit comprises an input circuit having a first input node and a second input node configured to receive a differential input signal; a first output circuit having a first capacitor coupled between the first input node and a first output node and a second capacitor coupled between the second input node and a second output node, wherein the first output circuit generates an output signal at the first output and the second output when the input signal is in a first frequency range; and a second output circuit comprising an amplifier having a first amplifier input coupled to the first input node and a second amplifier input coupled to the second input node, wherein the second output circuit generates an output signal when the input signal is in a second frequency range which extends lower than the first frequency range. A method of implementing a differential input receiver is also described. The circuits and methods also allow for offset compensation.

Circuit for and method of implementing a differential input receiver

A circuit for controlling output swing in a current-mode logic circuit is described. The circuit comprises a plurality of current-mode logic circuits coupled in series; a first current-mode logic circuit of the plurality of current-mode logic circuits coupled to provide a signal to a second current-mode logic circuit of the plurality of current-mode logic circuits; an amplitude detector coupled to detect an amplitude of the signal received at the second current-mode logic circuit; and a control circuit coupled to the amplitude detector; wherein the control circuit generates an amplitude control signal for a current-mode logic circuit of the plurality of current-mode logic circuits based upon a detected amplitude of the signal received at the second current-mode logic circuit. A method of controlling output swing in a current-mode logic circuit is also disclosed.

Circuits for and methods of controlling output swing in a current-mode logic circuit

An apparatus relating generally to voltage conversion includes an amplifier coupled to receive an input voltage and a reference voltage. First and second converters are coupled to the amplifier to receive a bias voltage. The first converter includes a first transconductor coupled to receive the bias voltage to adjust a first tail current, and a first differential input. A first inverter of the first converter has a first feedback device coupled input-to-output to provide a first transimpedance amplifier load. The first inverter is coupled to the first transconductor. The second converter includes a second transconductor coupled to receive the bias voltage to adjust a second tail current, and a second differential input. A second inverter of the second converter has a second feedback device coupled input-to-output to provide a second transimpedance amplifier load. The second inverter is coupled to the second transconductor.

High-speed analog comparator

An analog-to-digital converter ('ADC'). The ADC includes a bank of comparators and a window controller. The window controller is coupled to the bank of comparators to selectively activate first comparators of the bank of comparators associated with a window size and to selectively inactivate second comparators of the bank of comparators.

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Douglas, Ireland

Declan Carey