Abstract: A driver circuit includes a first inverter, a bias-control circuit, and a second inverter. The first inverter, which is connected between a first supply voltage and ground, receives an input data signal and generates an inverted version of the input data signal. The bias-control circuit, which is connected between a second supply voltage and the first inverter, receives the inverted version of the input data signal and a bias signal, and generates a level-shifted data signal based on the inverted version of the input data signal, the bias signal, and the second supply voltage. The bias-control circuit reduces a difference between voltage levels of the second supply voltage and the inverted version of the input data signal. The second inverter is connected between the second supply voltage and ground, and further connected to the bias-control circuit and first inverter and generates an output data signal.

Abstract: A system for serializing input data signals and generating an output data signal includes a FIFO memory that launches the input data signals at different phases of a clock signal. The system further includes multiple stages of a serializer circuit, and each stage of the serializer circuit receives a clock signal. Each successive stage includes half the number of serializer circuits that are included in the previous stage, and each successive stage is clocked by a clock signal that transitions at twice the frequency of the previous stage clock signal. The serializer circuits that belong to a single stage receive the clock signal with different phase. The phase and frequency of clock signals of serializer stages are adjusted such that a launched input data signal is outputted as the output data signal. Further, a critical path for each serializer circuit is equal to full clock cycle of the clock signal.

Abstract: A clock and data recovery (CDR) circuit includes first through ninth samplers, a clock recovery circuit, a level finding circuit, an offset voltage generator, and a data recovery circuit. Each of the first through ninth samplers samples a data signal based on one of first through ninth reference offset voltage levels to generate first through ninth intermediate signals, respectively. The clock recovery circuit generates the first through fourth clock signals based on the first, second, fifth, and eighth intermediate signals. The level finding circuit generates a band level signal by varying the third intermediate signal. The offset voltage generator generates one of: the fourth and seventh reference offset voltage levels, the fifth and eighth reference offset voltage levels, and the sixth and ninth reference offset voltage levels based on the band level signal. The data recovery circuit detects an output data signal based on the fourth through ninth intermediate signals.

Abstract: A clock and data recovery circuit includes a phase detector, an adder, and an oscillator circuit. The phase detector includes a sampling circuit, a comparison circuit, and a resampling circuit. The sampling circuit includes first through fourth flip-flops for receiving a data signal and first through fourth clock signals, and generating first through fourth sampling signals. The comparison circuit includes first through fourth logic gates for receiving the first through fourth sampling signals and generating first through fourth comparison signals, respectively. The resampling circuit includes fifth through eighth flip-flops for receiving the first through fourth comparison signals and the first through fourth clock signals, and generating first through fourth control signals, respectively. The adder receives the first through fourth control signals, and generates a frequency control signal. The oscillator circuit receives the frequency control signal, generates the first through fourth clock signals.

Abstract: A decision feedback equalizer (DFE) includes first through sixth flip-flops, and first and second summer circuits. The first through fourth flip-flops sample an analog input signal received at the first and second summer circuits, detect the logic level of a data bit in the analog input signal and generate the first through fourth compensated signals. The first multiplexer outputs at least one of the first and second compensated signals as a first feedback signal, based on a fourth feedback signal generated by the sixth flip-flop. The second multiplexer outputs at least one of the third and fourth compensated signals as a second feedback signal, based on a third feedback signal generated by the fifth flip-flop. The first and second feedback signals are multiplied by a weight coefficient and fed back to the first and second summer circuit, respectively, to compensate an error in the analog input signal.

Abstract: Embodiments of the present invention disclose an apparatus for managing clock duty cycle. The apparatus comprises a Duty Cycle Control Circuit (DCCC) for receiving at least an input clock signal and generating an output clock signal with adjustable duty cycle, a first Low-Pass Filter with Pull-Up Resistor (LPFPR) for receiving the output clock signal with adjustable duty cycle and simultaneously averaging and raising the common mode of the output thereof, a frequency divider for generating a signal with a 50% duty cycle, a second LPFPR for receiving the generated signal with 50% duty cycle and simultaneously averaging and raising the common mode of the output thereof and an OPAMP for receiving the outputs of the first and second LPFPRs for generating an equivalent reference signal to be fed to the DCCC as a control input, thereby facilitating correction of the duty cycle of the input clock signal.

Abstract: A decision feedback equalizer (DFE) includes first through sixth flip-flops, and first and second summer circuits. The first through fourth flip-flops sample an analog input signal received at the first and second summer circuits, detect the logic level of a data bit in the analog input signal and generate the first through fourth compensated signals. The first multiplexer outputs at least one of the first and second compensated signals as a first feedback signal, based on a fourth feedback signal generated by the sixth flip-flop. The second multiplexer outputs at least one of the third and fourth compensated signals as a second feedback signal, based on a third feedback signal generated by the fifth flip-flop. The first and second feedback signals are multiplied by a weight coefficient and fed back to the first and second summer circuit, respectively, to compensate an error in the analog input signal.

Abstract: A system and method for managing estimation and calibration of non-ideality of a Clock and Data Recovery circuit includes phase interpolators (PIs), first and second sets of delay elements, and a clock delay element. A first delay element of the first set of delay elements is programmed using a first digital delay control code (DDCC). The clock delay element is calibrated using a digital external delay control code (DEDCC) till a predetermined criterion is met, and is retained for subsequent use. The remaining delay elements of the first set of delay elements are separately calibrated based on the DEDCC. A first delay element of the second set of delay elements is programmed using a second DDCC. The DEDCC is readjusted for the second set of delay elements. The remaining delay elements of the second set of delay elements are separately calibrated based on the readjusted DEDCC.

Abstract: A clock and data recovery (CDR) circuit that receives an input signal and generates clock and sampled output signals includes a phase-frequency detector (PFD) circuit, a control circuit, a digital-to-analog converter (DAC), a current-controlled oscillator (CCO) and a data sampler. The PFD generates intermediate and fine digital control signals. The DAC receives the intermediate digital control signal as a coarse digital control signal and the fine digital control signal and generates an output current. The CCO receives the output current and generates the clock signal. The coarse digital control signal is used to coarse calibrate a frequency of the clock signal and the fine digital control signal is used to fine calibrate the frequency of the clock signal. The data sampler receives the clock signal and samples the input signal at the frequency of the clock signal to generate the sampled output signal.