Nested phase-locked loops (PLLs) utilize resonators of different quality factors, oscillation frequencies, and tunability. A reference clock signal for a first PLL is based on a free running bulk acoustic wave (BAW) resonator. The first PLL utilizes an LC oscillator as a voltage controlled oscillator. A crystal oscillator supplies a reference clock signal to a second PLL. Feedback dividers of the first and second PLLs are coupled to the LC oscillator. A delta sigma modulator coupled to the loop filter of the second PLL controls the feedback divider of the first PLL. The first PLL utilizes a high update rate to ensure that the jitter power spectral density is spread over a wide frequency range. The nested PLL architecture allows the overall phase noise plot to follow that of the crystal resonator at low frequencies, the BAW resonator at mid-frequencies, and the LC resonator at high frequencies.

Nested phase-locked loops (PLLs) utilize resonators of different quality factors, oscillation frequencies, and tunability. A reference clock signal for a first PLL is based on a free running bulk acoustic wave (BAW) resonator. The first PLL utilizes an LC oscillator as a voltage controlled oscillator. A crystal oscillator supplies a reference clock signal to a second PLL. Feedback dividers of the first and second PLLs are coupled to the LC oscillator. A delta sigma modulator coupled to the loop filter of the second PLL controls the feedback divider of the first PLL. The first PLL utilizes a high update rate to ensure that the jitter power spectral density is spread over a wide frequency range. The nested PLL architecture allows the overall phase noise plot to follow that of the crystal resonator at low frequencies, the BAW resonator at mid-frequencies, and the LC resonator at high frequencies.

An apparatus is comprised of a processor, a fast-locking Phase-Locked Loop Waveform Generator (PLLWG), an amplifier circuit, and a voltage controlled oscillator (VCO). The processor generates data program signals to program the PLLWG and generates a trigger command signal instructing the PLLWG to generate an analog tuning signal. The PLLWG, coupled to the processor, generates the analog tuning signal based on the trigger command signal. The amplifier circuit, coupled to the PLLWG, receives the analog tuning signal, amplify the analog tuning signal, and generates a control voltage. The VCO, coupled to the amplifier circuit, receives the control voltage and amplifies the control voltage to generate an amplified Radio Frequency (RF) channel frequency signal.

An IC, operable at a first clock phase, includes first and second IOs and a PLL. The PLL includes a control circuit, an input to receive a first clock signal, an output to output a second clock signal, and a first detector to generate a first phase difference signal from the first and second clock signals. The IC includes a second phase detector that is coupled to the PLL's output to receive the second clock signal and is coupled to the first IO to receive a third clock single from a second IC, which is operable at a second clock phase. The second detector generates a second phase difference signal from the second and third clock signals. If the PLL uses the second phase difference signal to generate the second clock signal, then the second clock signal is synchronized with the third clock signal for synchronous data transfer.

An IC, operable at a first clock phase, includes first and second IOs and a PLL. The PLL includes a control circuit, an input to receive a first clock signal, an output to output a second clock signal, and a first detector to generate a first phase difference signal from the first and second clock signals. The IC includes a second phase detector that is coupled to the PLL's output to receive the second clock signal and is coupled to the first IO to receive a third clock single from a second IC, which is operable at a second clock phase. The second detector generates a second phase difference signal from the second and third clock signals. If the PLL uses the second phase difference signal to generate the second clock signal, then the second clock signal is synchronized with the third clock signal for synchronous data transfer.

A system delays input clock signals using time-to-digital converters (TDCs) to convert edges or the clock signals to digital values and storing the digital values in a memory. The digital values are retrieved from the memory based on a desired delay. A time counter used by the TDCs to determine the edges is also used determine the delay. The accuracy and range of the delay depends on the time counter and size of the memory.

A system delays input clock signals using time-to-digital converters (TDCs) to convert edges or the clock signals to digital values and storing the digital values in a memory. The digital values are retrieved from the memory based on a desired delay. A time counter used by the TDCs to determine the edges is also used determine the delay. The accuracy and range of the delay depends on the time counter and size of the memory.

A phase locked loop having a charge pump is described. The charge pump relies on close matching of FETs (Field Effect Transistor) electrical parameters to FETs in a current reference circuit. To achieve close matching of FET electrical performance, FEOL (Front End Of Line), comprising all FET shapes, of the current pump is identical in shapes and layout to the current reference circuit. BEOL (Back End Of Line) differs between the charge pump and the current reference circuit. The charge pump and the current reference circuit are arranged in a row. A shield circuit having FEOL shapes and layout identical to the current pump may be placed at each end of the row.

A phase locked loop having a charge pump is described. The charge pump relies on close matching of FETs (Field Effect Transistor) electrical parameters to FETs in a current reference circuit. To achieve close matching of FET electrical performance, FEOL (Front End Of Line), comprising all FET shapes, of the current pump is identical in shapes and layout to the current reference circuit. BEOL (Back End Of Line) differs between the charge pump and the current reference circuit. The charge pump and the current reference circuit are arranged in a row. A shield circuit having FEOL shapes and layout identical to the current pump may be placed at each end of the row.

A clock generator calibration system can include a phased-locked loop and a correction circuit. The PLL can generate an output clock signal, and the correction circuit can adjust a frequency signal of the PLL based on a digital signal of the PLL. The digital signal can be generated based on the adjusted frequency signal.