In an embodiment, a circuit includes: a transformer defining an inductive footprint within a first layer; a grounded shield bounded by the inductive footprint within a second layer separate from the first layer; and a circuit component bounded by the inductive footprint within a third layer separate from the second layer, wherein: the circuit component is coupled with the transformer through the second layer, and the third layer is separated from the first layer by the second layer.

Techniques are provided for reducing or mitigating phase noise of a digital phase lock loop or the system depending on the digital phase lock loop. In an example, a multiple-mode digital phase lock loop can include a digital phase lock loop (DPLL), multiple frequency scalers configured to receive a reference clock, and a multiplexer configured to receive a mode command signal and to couple an output of one of the multiple frequency scalers to an input of the DPLL in response to a state of the mode command signal.

Systems, apparatuses, and methods for implementing a hybrid asynchronous gray counter with a non-gray zone detector are described. A circuit includes an asynchronous gray counter coupled to control logic. The control logic programs the asynchronous gray counter to operate in different modes to perform various functions associated with a high-performance phase-locked loop (PLL). In a first mode, the asynchronous gray counter serves as a frequency detector to count oscillator cycles within a reference clock cycle. In a second mode, the asynchronous gray counter serves as a coarse phase detector to detect a phase error between a feedback clock and a reference clock. In a third mode, the asynchronous gray counter serves as a multi-modulus divider to divide an oscillator clock down to create a feedback clock. Using a single asynchronous gray counter for three separate functions reduces power consumption and area utilization.

Methods and digital circuits providing frequency correction to frequency synthesizers are disclosed. An FLL digital circuit is provided that is configured to handle a reference frequency that is dynamic and ranges over a multi-decade range of frequencies. The FLL circuit includes a digital frequency iteration engine that allows for detection of disappearance of a reference frequency. When the digital frequency iteration engine detects that the reference frequency signal is not available, the oscillator generated frequency is not corrected, and the last value of the oscillator generated frequency is held until the reference frequency signal becomes available again. This FLL circuit is also preceded by a low-pass filter which is dynamically tuned to the frequency to which the FLL locks, eliminating harmonic components in the original signal which might otherwise cause errors in frequency estimation.

A mobile communication device adapted to perform spur relocation for a digital phase-locked loop includes a receiver to determine a first frequency channel of interest and to identify a first frequency command word corresponding to the first frequency channel of interest. The mobile communication device further includes control logic circuitry to identify a first frequency at which a first fractional spur associated with the first frequency command word starts to occur and to determine whether the identified first frequency is within the first frequency channel of interest. In addition, the mobile communication device includes a programmable feedback divider configured to change the first frequency command word to a second frequency command word, wherein a second fractional spur associated with the second frequency command word occurs at a second frequency outside the first frequency channel of interest.

An oscillator circuit includes an oscillating unit, a counter unit, and a set value generator. The oscillating unit is configured to output an oscillation signal having a frequency corresponding to an input frequency setting value. The counter unit is configured to count a number of pulses of the oscillation signal during a time period corresponding to a period of a reference signal input from outside. The set value generator is configured to generate the frequency setting value every predetermined time period based on the count of the pulses counted by the counter unit.

Embodiments related to systems, methods, and computer-readable media to enable a digital phase locked loop are described. In one embodiment, a digital synthesizer comprises a digital phase locked loop with detection circuitry to calculate an estimate of a magnitude and a phase of a spurious response from an error signal within the digital phase locked loop. The digital phase locked loop further comprises generation circuitry to generate an inverse spur based on the estimate of the magnitude and the phase, and further comprises injection circuitry to inject the inverse spur into the digital phase locked loop. In some embodiments, least mean squares (LMS), recursive least squares (RLS), or other such adaptation is used to estimate the magnitude and phase of the spurious response.

A frequency-to-digital-converter based PLL (FDC-PLL) that implements the functionality of a charge pump and analog-to-digital converter (ADC) with a dual-mode ring oscillator (DMRO) and digital logic. Preferred embodiments of the invention include circuit-level techniques that provide better spurious tone performance and very low phase noise with lower power dissipation and supply voltage than prior digital PLLs known to the inventors

A phase detector includes a counter to generate the integer portion of a number of complete cycles of an output clock at each active edge of a reference clock. A time to digital converter in the phase detector generates the fractional portion of the number of complete cycles of the output clock at each active edge of the reference clock. The sum of the fractional portion and the integer portion is subtracted from an accumulated value obtained by accumulating a pre-determined number to generate an error signal as the output of the phase detector. The counter is read at an active edge of one of two re-timed clocks derived from the reference clock. Each of the two re-timed clocks is generated based on a comparison of the fractional portion with a pair of thresholds. Errors due to metastability in reading the counter are thereby avoided.

A phase locked loop has an integer phase detector to detect an integer phase by measuring a cycle number, a fractional phase detector to detect a fractional phase of smaller than one cycle between a reference signal and the oscillation signal, a frequency error generator to generate a frequency error signal between the reference signal and the oscillation signal, a glitch corrector to correct the frequency error signal to generate and output a glitch-corrected signal and the frequency error signal, a phase error generator to generate a phase error by integrating an output signal of the glitch corrector, an oscillator controller to control an oscillation frequency of the oscillation signal, and a synchronous detector to detect whether a phase of the reference signal and a phase of the oscillation signal are in an phase-lock state, and to stop detection of the integer phase when the phase-lock state is detected.