A synchronizer circuit includes a first synchronizer having a first input for receiving a signal associated with a first clock signal, a second input for receiving a second clock signal, and an output for providing a synchronizer circuit output signal; a second synchronizer having a first input for receiving the signal associated with the first clock signal, a second input for receiving the second clock signal, and an output; a detection stage having a first input coupled to the output of the first synchronizer and to the output of the second synchronizer, a second input for receiving the second clock signal, and an output; and a fault output stage having a first input coupled to the detection stage, a second input for receiving the second clock signal, and an output for providing a fault output signal.

A synchronizer circuit includes a first synchronizer having a first input for receiving a signal associated with a first clock signal, a second input for receiving a second clock signal, and an output for providing a synchronizer circuit output signal; a second synchronizer having a first input for receiving the signal associated with the first clock signal, a second input for receiving the second clock signal, and an output; a detection stage having a first input coupled to the output of the first synchronizer and to the output of the second synchronizer, a second input for receiving the second clock signal, and an output; and a fault output stage having a first input coupled to the detection stage, a second input for receiving the second clock signal, and an output for providing a fault output signal.

A signal receiving circuit includes a summing circuit, a clocked latch circuit and a feedback circuit. The summing circuit generates a summing signal based on an input signal and a feedback signal. The clocked latch circuit generates a sampling signal by sampling the summing signal in synchronization with a clock signal. The feedback circuit generates the feedback signal by selecting one among a plurality of coefficients based on the sampling signal.

A method for synchronization of an input signal includes providing the input signal to a first signal path associated with a first clock and to a second signal path associated with a second clock, detecting an edge of the input signal by detecting values of the input signal along the first signal path at a first rising edge of the first clock and at a second rising edge of the first clock, detecting a value of the input signal along the second signal path at an edge of the second clock, and selecting the input signal from the first signal path or from the second signal path according to the detected value of the input signal along the second path when an edge of the input signal along the first path is detected.

A semiconductor device outputs, as an output signal synchronized to a phase-locked loop clock signal, a synchronized input signal that is synchronized to a reference clock signal of a phase-locked loop circuit. The semiconductor device includes the phase-locked loop circuit, a first flip-flop that receives the input signal in synchronization with the reference clock signal on the basis of a feedback signal inputted to a phase comparator of the phase-locked loop circuit 10, and a second flip-flop that receives an output from the first flip-flop on the basis of the phase-locked loop clock signal. The second flip-flop outputs the output from the first flip-flop as the output signal. A setup time to synchronize the input signal to the phase-locked loop clock signal is set to one half of a period of the reference clock signal.

A example receiver includes analog circuitry configured to equalize and amplify an input signal and provide an analog signal as output; clock data recovery (CDR) circuitry configured to recover data clocks and edge clocks from the analog signal; a plurality of eye height optimization circuits, each of the plurality of eye height optimization circuits configured to, based on a respective data pattern of a plurality of data patterns, sample the analog signal based on the data clocks and the edge clocks, feed back first information to the analog circuitry for adjusting the eye amplitude, and feed back second information to the CDR circuitry for adjusting the data clocks; and an eye width optimization circuit configured to receive data and edge samples from the plurality of eye height optimization circuits, feed back third information to the CDR circuitry to adjust the edge clocks, and feed back fourth information to the analog circuitry to adjust the equalization.

Methods and systems are described for receiving a signal to be sampled and responsively generating, at a pair of common nodes, a differential current representative of the received signal, receiving a plurality of sampling interval signals, each sampling interval signal received at a corresponding sampling phase of a plurality of sampling phases, for each sampling phase, pre-charging a corresponding pair of output nodes using a pre-charging FET pair receiving the sampling interval signal, forming a differential output voltage by discharging the corresponding pair of output nodes via a discharging FET pair connected to the pair of common nodes, the FET pair receiving the sampling interval signal and selectively enabling the differential current to discharge the corresponding pair of output nodes, and latching the differential output voltage.

An electronic system includes transmitting circuitry of a first clock domain and receiving circuitry of a second domain. The transmitting circuitry re-times a digital input signal with rising edges of a clocking signal of the first clock domain when a phase of the clocking signal of the first clock domain leads a phase of a clocking signal associated with the digital input signal. Otherwise, the transmitting circuitry re-times the digital input signal with falling edges of the clocking signal of the first clock domain when the phase of the clocking signal of the first clock domain does not lead the phase of the clocking signal associated with a digital input signal. The receiving circuitry receives the re-timed digital input signal from the transmitting circuitry. Thereafter, the receiving circuitry re-times the re-timed digital input signal with rising edges of a phase of a clocking signal associated with the re-timed digital input signal when the phase of the clocking signal associated with the re-timed digital input signal leads a phase of a clocking signal of the second clock domain. Otherwise, the receiving circuitry re-times the re-timed digital input signal with falling edges of the phase of a clocking signal associated with the re-timed digital input signal when the phase of the clocking signal associated with the re-timed digital input signal does not lead the phase of a clocking signal of the second clock domain.

According to one embodiment, an electronic device executes decision feedback-type equalization for input data using a tap coefficient while updating the tap coefficient. The electronic device includes a first memory cyclically receiving a tap coefficient, holing the tap coefficient received, and cyclically outputting the tap coefficient held, and a second memory receiving the tap coefficient cyclically output from the first memory and holding the tap coefficient received. The tap coefficient cyclically output from the first memory is delayed by at least one cycle than the tap coefficient cyclically received by the first memory. The tap coefficient held in the second memory is used for the decision feedback-type equalization in a no-signal period in which no input data exist.

A semiconductor apparatus may include a first semiconductor apparatus configured to transmit a first input signal as first data in synchronization with a first edge of a first clock signal having a first frequency. The semiconductor apparatus may also include a second semiconductor apparatus including: a first storage unit, configured to receive the first data as a set signal and output a second input signal as an internal signal in synchronization with a first edge of a second clock signal having a second frequency; and a second storage unit, to configured to output the internal signal as second data in synchronization with a second edge of the second clock signal.