Abstract: An integrated circuit with a pipeline analog-to-digital (A/D) converter and associated calibration circuitry is provided. The A/D converter may include multiple series-connected pipeline stages at least some of which are implemented using a switched capacitor configuration. The calibration circuitry may include an analog error correction circuit, a digital error correction circuit, and a calibration control circuit for coordinating the operation of the analog and digital error correction circuits. During calibration operations, the analog error correction circuit may be used to suitably adjust a gain setting for each pipeline stage, whereas the digital error correction circuit may be used to compute a code offset value for each pipeline stage. Calibration may proceed from a least-significant-bit pipeline stage towards a most-significant-bit pipeline stage, one stage at a time.

Abstract: One embodiment relates to a receiver circuit for multi-level amplitude signaling which includes at least three amplitude levels for each symbol period. The receiver circuit includes a peak detector, a reference voltage generator, and a comparator circuit. The peak detector is arranged to detect a peak voltage of the multi-level amplitude signal, and the reference voltage generator uses the peak voltage to generate multiple reference voltages. The comparator circuit uses the multiple reference voltages to detect an amplitude level of the multi-level amplitude signal. Other embodiments and features are also disclosed.

Abstract: System, methods, and devices for determining an eye diagram of a serial input signal to an integrated circuit without an oscilloscope are provided. For example, one embodiment of an integrated circuit device may be capable of determining an eye diagram associated with a serial input signal either during or after equalization. The device may include an equalizer and eye viewer circuitry configured to select a node of the equalizer for eye monitoring of the input signal, which may be during or after equalization. In one embodiment, the eye viewer circuitry may provide a separate sampler for each respective node, while sharing a control logic and phase interpolator among the samplers. The eye viewer circuitry may determine horizontal and vertical boundaries of the eye diagram associated with the serial input signal, as seen from the selected node of the equalizer.

Abstract: One embodiment relates a method of correcting skew and/or duty cycle distortion in a differential signal using a transmitter buffer circuit. Skew and/or duty cycle distortion may be detected in the differential signal. Delay times for at least two variable-delay buffer circuits are adjusted. The variable-delay buffer circuits may have outputs coupled to control gates of pull-up and pull-down transistors coupled to one or more output nodes of the transmitter buffer circuit. Other embodiments, aspects, and features are also disclosed.

Abstract: Transmitter equalizer circuitry, e.g., for a serial, digital, data signal, includes tapped delay line circuitry for outputting a plurality of differently delayed versions of the signal propagating through the delay line circuitry. The equalizer circuitry also includes a plurality of electrical current digital-to-analog converters (“DACs”). The equalizer circuitry still further includes controllable (e.g., programmable) routing circuitry for selectably routing the delayed versions of the signal to the various DACs. The current strengths employed by the various DACs are also preferably controllable (e.g., programmable).

Abstract: Integrated circuits having analog-to-digital converters are provided. Analog-to-digital converters may contain latched comparators. A latched comparator may include inputs configured to receive a differential input voltage signal, a differential reference voltage signal, and a clock signal. The comparator may include a preamplifier, a latching circuit, a level shifter, and a flip-flop coupled in series. The preamplifier may include large input transistors for minimizing offset, stacked tail transistors, and diode-connected load transistors for minimizing kickback noise. The preamplifier may be used to generate amplified voltage signals. The latching circuit may include a first pair of cross-coupled pull-down transistors, a second pair of cross-coupled pull-up transistors, and precharge transistors.

Abstract: Systems and methods of calibrating a successive approximation register analog-to-digital converter (ADC) are disclosed. A plurality of capacitor stages, a first capacitor array, and a first capacitor stage are coupled in parallel. A capacitance of the first capacitor stage is compared to a sum of capacitances of the plurality of capacitor stages and of the first capacitor array. In response to the comparing, the capacitance of the first capacitor stage is increased by increasing the capacitance of a second capacitor array if the capacitance of the first capacitor stage is less than the sum of the capacitances of the plurality of capacitor stages and of the first capacitor array.

Abstract: One embodiment relates to an integrated circuit which includes a transmitter buffer circuit, a duty cycle distortion (DCD) detector, correction logic, and a duty cycle adjuster. The DCD detector is configured to selectively couple to the serial output of the transmitter buffer circuit. The correction logic is configured to generate control signals based on the output of the DCD detector. The duty cycle adjuster is configured to adjust a duty cycle of the serial input signal based on the control signals. Another embodiment relates to a method of correcting duty cycle distortion in a transmitter. Other embodiments and features are also disclosed.

Abstract: One embodiment relates to a clocking network interconnecting an array of transceivers. The clocking network includes first and second series of multiplexers, each multiplexer in the first and second series being adjacent to a transceiver. The first series of multiplexers selectively transmits clock signals in a first direction of the array, and the second series of multiplexers selectively transmits clock signals in a second direction of the array. Another embodiment relates to an integrated circuit with a programmable interface. The integrated circuit includes an array of physical media attachment circuits, phase-locked loop circuits, and a clock distribution network. The clock distribution network is arranged to be programmed into multiple segments. Each segment distributes a clock signal to a bounded range of the physical media attachment circuits in the array. Another embodiment relates to a method of distributing clock signals in an integrated circuit. Other embodiments and features are also disclosed.

Abstract: A high-speed differential comparator circuit is provided with an accurately adjustable threshold voltage. Differential reference voltage signals are provided to control the threshold voltage of the comparator. The common mode voltage of the reference signals preferably tracks the common mode voltage of the differential high-speed serial data signal being processed by the comparator circuit.

Abstract: Disclosed are apparatus and methods to advantageously manage transceiver power in an automated manner using adaptation logic that may be implemented on a same integrated circuit as the transceiver circuitry. In one embodiment, a power-consuming component of the transceiver is turned on at a lowest power setting. A determination is made as to whether a first set of eye opening data for a serial data signal meets preset criteria. If the preset criteria are not met by the first set of eye opening data, then the power-consuming component is changed to a second lowest power setting. Another embodiment relates to an integrated circuit including a receiver buffer, a receiver equalization circuit, an eye viewer circuit and adaptation logic. The adaptation logic is configured to obtain the eye opening data and to adapt the receiver equalization circuit to conserve power used. Other embodiments, aspects and features are also disclosed.

Abstract: An integrated circuit (“IC”) includes circuitry for use in testing a serial data signal. One such IC includes circuitry for transmitting the serial data signal with optional jitter, optional noise, and/or controllably variable drive strength. One such IC also includes circuitry for receiving the serial data signal and performing a bit error rate (“BER”) analysis in such a signal. Such an IC provides output signals indicative of results of its operations. One such IC operates in various modes to perform or at least emulate functions of an oscilloscope, a bit error rate tester, etc., for testing signals and circuitry with respect to jitter-tolerance, noise-tolerance, etc.

Abstract: One embodiment relates to a receiver circuit for multi-level amplitude signaling which includes at least three amplitude levels for each symbol period. The receiver circuit includes a peak detector, a reference voltage generator, and a comparator circuit. The peak detector is arranged to detect a peak voltage of the multi-level amplitude signal, and the reference voltage generator uses the peak voltage to generate multiple reference voltages. The comparator circuit uses the multiple reference voltages to detect an amplitude level of the multi-level amplitude signal. Other embodiments and features are also disclosed.

Abstract: One embodiment relates to an integrated circuit which includes a transmitter buffer circuit, a duty cycle distortion (DCD) detector, correction logic, and a duty cycle adjuster. The DCD detector is configured to selectively couple to the serial output of the transmitter buffer circuit. The correction logic is configured to generate control signals based on the output of the DCD detector. The duty cycle adjuster is configured to adjust a duty cycle of the serial input signal based on the control signals. Another embodiment relates to a method of correcting duty cycle distortion in a transmitter. Other embodiments and features are also disclosed.

Abstract: Various methods and structures related to clock distribution for flexible channel bonding are disclosed. One embodiment provides a clock network in physical media attachment (“PMA”) circuitry, a specific type or portion of system interconnect circuitry, arranged in pairs of channel groups. In one embodiment, clock generation circuitry blocks (“CGBs”) in each pair of channel groups receives outputs of multiple phased locked loop circuits (“PLLs”) which can be selectively utilized by the CGBs to generate PMA clock signals. In another embodiment, the CGBs can also select output of a clock data recovery (“CDR”)/transmit PLL circuitry block in one of the channels of a channel group of the pair of channel groups. In one embodiment, first groups of connection lines couple circuitry in a channel group pair such that a designated CGB in each channel group pair can provide clock signals to one or more of the channels in the channel group pair.

Abstract: Systems, methods, and devices for determining an eye diagram of a serial input signal to an integrated circuit without an oscilloscope are provided. For example, one embodiment of an integrated circuit device may be capable of determining an eye diagram associated with an equalized serial input signal. The device may include an equalizer and eye viewer circuitry. The equalizer may receive and perform equalization on a serial input signal to produce the equalized serial input signal, and the eye viewer circuitry may determine horizontal and vertical boundaries of the eye diagram associated with the equalized serial input signal.

Abstract: One embodiment relates to a receiver circuit for a data link. The receiver circuit includes at least a first signal path, a second signal path, and a path selector circuit. The first signal path includes first equalization circuitry, and the second signal path includes second equalization circuitry. The path selector circuit is configured to select one signal path of the first and second signal paths. Other embodiments and features are also disclosed.

Abstract: An IC that includes an eye viewer and a BER checker coupled to the eye viewer, where the BER checker receives a serial data signal from the eye viewer, is provided. In one implementation, the BER checker receives the serial data signal from the eye viewer without the serial data signal passing through a deserializer. In one implementation, the BER checker compares the serial data signal against a reference data signal to determine the BER for the serial data signal. In one implementation, the IC includes an IC core coupled to the eye viewer and the BER checker, where the BER checker is outside the IC core. In one implementation, the BER checker is a dedicated BER checker. In one implementation, the BER checker includes an exclusive OR gate, a programmable delay circuit coupled to the exclusive OR gate, and an error counter coupled to the exclusive OR gate.

Abstract: A transmitter circuit is operable to provide an output signal in response to a first periodic signal. A multiplexer circuit is operable to provide a second periodic signal as a selected signal during a first phase of operation. The multiplexer circuit is operable to provide the output signal of the transmitter circuit as the selected signal during a second phase of operation. A sampler circuit is operable to generate first samples of the selected signal during the first phase of operation. The sampler circuit is operable to generate second samples of the selected signal during the second phase of operation. A duty cycle control circuit is operable to adjust a duty cycle of the first periodic signal based on the first and the second samples.

Abstract: A buffer circuit includes first and second inputs and first and second outputs. The buffer circuit is configurable to buffer a differential input signal received at the first and the second inputs to generate a differential output signal at the first and the second outputs in a current mode logic buffer mode based on a control signal. The buffer circuit is configurable to buffer the differential input signal to generate the differential output signal in an H-bridge buffer mode based on the control signal.