A phase locked loop, for a particularly in a beamforming system comprises a loop filter (1) to provide a control signal (FC) to a controllable oscillator (2); a frequency divider (3) configured to provide a first feedback signal (FB) and a second feedback signal (FBD) in response to an oscillator signal (FO), the second feedback signal (FBD) delayed with respect to the first feedback signal (FB); a first comparator path (4) configured to receive the first feedback signal (FB) and a second comparator path (5) configured to receive the second feedback signal (FBD), each of the first and second comparator path (4, 5) configured to provide a respective current signal (CS1, CS2) to the loop filter (1) in response to a respective adjustment signal (FA1, FA2) and a phase deviation between a common reference signal (FR) and the respective feedback signal (FB, FBD).

A circuit includes a first signal swapper including a first terminal coupled to a first current source, a second terminal coupled to a second current source, a third terminal coupled to a first current terminal of a first transistor, and a fourth terminal coupled to a third current terminal of a second transistor. The first signal swapper couples the first and second terminals to the third and fourth terminals responsive to a first control signal. First and second switches couple to a gate of the first transistor. The first switch receives the input oscillation signal and the second switch receives a first reference voltage. Third and fourth switches couple to a gate of the second transistor. The third switch receives the input oscillation signal and the fourth switch receives the first reference voltage. A second signal swapper couples to the first signal swapper and to the first and second transistors.

A circuit includes a first signal swapper including a first terminal coupled to a first current source, a second terminal coupled to a second current source, a third terminal coupled to a first current terminal of a first transistor, and a fourth terminal coupled to a third current terminal of a second transistor. The first signal swapper couples the first and second terminals to the third and fourth terminals responsive to a first control signal. First and second switches couple to a gate of the first transistor. The first switch receives the input oscillation signal and the second switch receives a first reference voltage. Third and fourth switches couple to a gate of the second transistor. The third switch receives the input oscillation signal and the fourth switch receives the first reference voltage. A second signal swapper couples to the first signal swapper and to the first and second transistors.

A semiconductor device includes an input/output circuit to which a signal is input or from which a signal is output; a first terminal connected to a power line of the input/output circuit; a second terminal connected to the power line; a resistance element connected between the second terminal and the power line; and a first capacitance element connected between the second terminal and a ground terminal. The semiconductor device can suppress a resonance phenomena and Volt age variation caused by impedance of the power line.

A sub-sampling phase-locked loop is described, which comprises a digital-to-time converter, a sampler module, an interpolator, and a voltage controlled oscillator. The digital-to-time converter is configured to provide a first delay signal SDLY1 at a first point t1 in time and a second delay signal SDLY2 at a second point in time t2. The sampler module is configured to provide a first sample S1 of the oscillator output signal SOUT at the first point in time t1 and a second sample S2 of the oscillator output signal SOUT at the second point in time t2. The interpolator is configured to provide a sampler signal SSAMPL by interpolating the first sample S1 and the second sample S2. The voltage controlled oscillator is configured to control the oscillator output signal SOUT based on the sampler signal SSAMPL.

A clock and data recovery circuit with jitter tolerance enhancement is provided. The CDR circuit includes: a bang-bang phase detector, a digital filter, a digitally controlled oscillator, and an adaptive loop gain control circuit. The CDR circuit detects a loop bandwidth variation and adjusts the loop bandwidth of CDR circuit by adjusting proportional path and integral path gain factors of the digital filter of the CDR circuit. The loop gain controller uses two methods to adjust the loop gain in CDR circuit: bang-bang adjusting method and linear adjusting method.

A sub-sampling phase-locked loop is described, which comprises a digital-to-time converter, a sampler module, an interpolator, and a voltage controlled oscillator. The digital-to-time converter is configured to provide a first delay signal (S.sub.DLY1) at a first point (t.sub.1) in time and a second delay signal (S.sub.DLY2) at a second point in time (t.sub.2). The sampler module is configured to provide a first sample (S.sub.1) of the oscillator output signal (S.sub.OUT) at the first point in time (t.sub.1) and a second sample (S.sub.2) of the oscillator output signal (S.sub.OUT) at the second point in time (t.sub.2). The interpolator is configured to provide a sampler signal (S.sub.SAMPL) by interpolating the first sample (S.sub.1) and the second sample (S.sub.2). The voltage controlled oscillator is configured to control the oscillator output signal (S.sub.OUT) based on the sampler signal (S.sub.SAMPL).

A charge pump driver circuit comprises an output stage and a current generator component. The output stage is arranged to receive at an input node thereof a control current signal and comprises a resistance network coupled between the input node thereof and a reference voltage node and arranged to provide a resistive path through which the control current signal flows. The output stage is arranged to generate at an output node thereof a charge pump control voltage signal based on the voltage level at the input node thereof. The current generator component is arranged to receive an indication of a voltage level of a charge pump output signal, and to generate a feedback current dependent on the voltage level of the output signal, wherein the feedback current is injected into the resistive path of the resistance network through which the control current signal flows.

A phase locked loop has a frequency divider included in a feedback path. The frequency divider generates a first output and a delayed output. The phase locked loop also includes a charge pump to generate an output current based on the first output and the delayed output of the frequency divider.

Embodiments include systems and methods for calibrating clocking circuits for improved jitter performance. Embodiments operate in context of a clocking circuit coupled with a transceiver system that has a receiver that tracks a recovered clock phase according to a tracking code. For example, candidate configurations can be identified, each corresponding to a different respective combination of parameter values for programmable clocking circuit parameters. For each candidate configuration, embodiments can configure the clocking system accordingly, and can sample the tracking code over a sample window to measure a tracking code spread for the candidate configuration. The clocking circuit can be programmed according to which of the candidate configurations manifested a minimum tracking code spread, thereby effectively configuring the clocking circuit for minimum jitter generation and optimizing jitter performance of the transceiver.