Abstract: A baud-rate phase detector uses two error samplers. One error sampler is used to determine whether the sampling time is too early error detection. The other is used to determine whether sampling time is too late. The early error sampler is configured to use a first threshold voltage. The late error sampler is configured to use a second threshold voltage. By adjusting the voltage difference between the first threshold voltage and the second threshold voltage, the phase difference between the local timing reference clock and the transitions of the data signal may be adjusted. The phase difference between the local timing reference clock and the transitions of the data signal may be adjusted to improve or optimize a desired receiver characteristic such as bit error rate or signal eye opening.

Abstract: An integrated circuit that includes a feedback loop to adapt receiver parameters. The feedback loop includes a receiver to sample a signal and produce a sampled signal sequence. The feedback loop also includes a first pattern counter to detect and count occurrences of a first pattern in the sampled signal sequence, and a second pattern counter to detect and count occurrences of a second pattern in the sampled signal sequence. Control circuitry coupled to the receiver adapts a parameter value of the receiver to minimize a difference between a first ratio and a second ratio. The first ratio is a target ratio. The second ratio is between a first counted number of occurrences of the first pattern in the sampled signal sequence and a second counted number of occurrences of the second pattern in the sample signal sequence.

Abstract: Disclosed is a successive approximation register (SAR) analog to digital converter (ADC) that uses two or more comparators. This allows the output of one comparator to be latched while the other comparators are comparing and switching. Statistical measures are used to correct the offsets of one or more of the comparators. If a statistically significant mismatch in the number of 1's and 0's occurs in a subset of the bits, adjustments to the offsets of one or more of the comparators are made until there is roughly an equal number of 1 and 0 values. This can reduce or eliminate the need for dedicated offset correction cycles.

Abstract: A phase rotator receives control signals and thermometer coded signals that specifies the phase of an output signal. The phase rotator may be used, for example, by a clock and data recovery (CDR) circuit to continually rotate the phase of a clock to compensate for phase/frequency mismatches between received data and the clock. The control signals determine the phase quadrant (i.e., 0°-90°, 90°-180°, etc.) of the output signal. The thermometer coded signals determine the phase of the output signal within a quadrant by steering a set of bias currents between two or more nodes. The set of bias currents are selected to reduce the non-linearity between the thermometer coded value and the phase of the output signal.

Abstract: A phase rotator receives control signals and thermometer coded signals that specifies the phase of an output signal. The phase rotator may be used, for example, by a clock and data recovery (CDR) circuit to continually rotate the phase of a clock to compensate for phase/frequency mismatches between received data and the clock. The control signals determine the phase quadrant (i.e., 0°-90°, 90°-180°, etc.) of the output signal. The thermometer coded signals determine the phase of the output signal within a quadrant by steering a set of bias currents between two or more nodes. The set of bias currents are selected to reduce the non-linearity between the thermometer coded value and the phase of the output signal.

Abstract: A phase-locked loop (PLL) includes a phase-frequency detector that compares a reference signal to a feedback signal. The difference in phase between the reference signal and the feedback signal is encoded as digital pulses on one or more outputs of the phase-frequency detector. The digital output pulses from the phase-frequency detector are duplicated and delayed multiple times in a non-overlapping manner before being input to the loop filter or voltage controlled oscillator (VCO) of the PLL.

Abstract: A phase rotator receives control signals and thermometer coded signals that specifies the phase of an output signal. The phase rotator may be used, for example, by a clock and data recovery (CDR) circuit to continually rotate the phase of a clock to compensate for phase/frequency mismatches between received data and the clock. The control signals determine the phase quadrant (i.e., 0°-90°, 90°-180°, etc.) of the output signal. The thermometer coded signals determine the phase of the output signal within a quadrant by steering a set of bias currents between two or more nodes. The set of bias currents are selected to reduce the non-linearity between the thermometer coded value and the phase of the output signal.

Abstract: A clock and data recovery circuit (CDR) includes a digitally controlled oscillator (DCO). A data sampler is coupled to receive a clock signal from the DCO. A deserializer includes an input coupled to an output of the data sampler. A first phase detector is coupled between a first output of the deserializer and a first input of the DCO. A second phase detector is coupled to a second output of the deserializer. An accumulator is coupled between an output of the second phase detector and a second input of the DCO. A frequency lock detection block is coupled to an output of the accumulator. An eye monitor is coupled to an input of the data sampler. The first phase detector controls a delay of the DCO and the accumulator controls a frequency of the DCO. An edge mute signal is coupled to the deserializer.

Abstract: A clock and data recovery circuit (CDR) includes a digitally controlled oscillator (DCO). A data sampler is coupled to receive a clock signal from the DCO. A deserializer includes an input coupled to an output of the data sampler. A first phase detector is coupled between a first output of the deserializer and a first input of the DCO. A second phase detector is coupled to a second output of the deserializer. An accumulator is coupled between an output of the second phase detector and a second input of the DCO. A frequency lock detection block is coupled to an output of the accumulator. An eye monitor is coupled to an input of the data sampler. The first phase detector controls a delay of the DCO and the accumulator controls a frequency of the DCO. An edge mute signal is coupled to the deserializer.

Abstract: A clock and data recovery circuit (CDR) includes a digitally controlled oscillator (DCO). A data sampler is coupled to receive a clock signal from the DCO. A deserializer includes an input coupled to an output of the data sampler. A first phase detector is coupled between a first output of the deserializer and a first input of the DCO. A second phase detector is coupled to a second output of the deserializer. An accumulator is coupled between an output of the second phase detector and a second input of the DCO. A frequency lock detection block is coupled to an output of the accumulator. An eye monitor is coupled to an input of the data sampler. The first phase detector controls a delay of the DCO and the accumulator controls a frequency of the DCO. An edge mute signal is coupled to the deserializer.

Abstract: A clock and data recovery circuit (CDR) includes a digitally controlled oscillator (DCO). A data sampler is coupled to receive a clock signal from the DCO. A deserializer includes an input coupled to an output of the data sampler. A first phase detector is coupled between a first output of the deserializer and a first input of the DCO. A second phase detector is coupled to a second output of the deserializer. An accumulator is coupled between an output of the second phase detector and a second input of the DCO. A frequency lock detection block is coupled to an output of the accumulator. An eye monitor is coupled to an input of the data sampler. The first phase detector controls a delay of the DCO and the accumulator controls a frequency of the DCO. An edge mute signal is coupled to the deserializer.

Abstract: A decision feedback equalizer, transceiver, and method are provided, the equalizer having at least one comparator, the at least one comparator comprising a first stage, comprising a main branch having two track switches with a resistive load, an offset cancellation branch, a plurality of tap branches with transistor sizes smaller than the main branch, in which previous decisions of the equalizer are mixed with the tap weights using current-mode switching, and a cross coupled latch branch; and a second stage, comprising a comparator module for making decisions based on the outputs of the first stage and a clock input, and a plurality of flip-flops for storing the output of the comparator module.

Abstract: A decision feedback equalizer, transceiver, and method are provided, the equalizer having at least one comparator, the at least one comparator comprising a first stage, comprising a main branch having two track switches with a resistive load, an offset cancellation branch, a plurality of tap branches with transistor sizes smaller than the main branch, in which previous decisions of the equalizer are mixed with the tap weights using current-mode switching, and a cross coupled latch branch; and a second stage, comprising a comparator module for making decisions based on the outputs of the first stage and a clock input, and a plurality of flip-flops for storing the output of the comparator module.