Abstract: An apparatus includes a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate a first code by counting a number of cycles of an input clock signal during a period. The period may be determined by an output clock signal and a second code. The second circuit may be configured to generate a third code by a delta-sigma modulation of the first code. The third circuit may be configured to generate the output clock signal in response to the third code. An accuracy of a frequency of the output clock signal may be determined by a current value of the second code.

Abstract: An apparatus includes a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate a first code by counting a number of cycles of an input clock signal during a period. The period may be determined by an output clock signal and a second code. The second circuit may be configured to generate a third code by a delta-sigma modulation of the first code. The third circuit may be configured to generate the output clock signal in response to the third code. An accuracy of a frequency of the output clock signal may be determined by a current value of the second code.

Abstract: An apparatus includes a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate a first code by counting a number of cycles of an input clock signal in a period determined by (i) an output clock signal and (ii) a second code. The second code may be variable. The second circuit may be configured to generate a third code by a delta-sigma modulation of the first code. The third circuit may be configured to generate the output clock signal (i) in response to the third code and (ii) within an accuracy determined the second code.

Abstract: An apparatus includes a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate a first code by counting a number of cycles of an input clock signal in a period determined by (i) an output clock signal and (ii) a second code. The second code may be variable. The second circuit may be configured to generate a third code by a delta-sigma modulation of the first code. The third circuit may be configured to generate the output clock signal (i) in response to the third code and (ii) within an accuracy determined the second code.

Abstract: A frequency synthesizer comprising a first phase locked loop (PLL) circuit coupled to receive a reference frequency signal from a reference oscillator, the first PLL circuit comprising a first voltage controlled oscillator (VCO) having a bulk acoustic wave (BAW) resonator and a first fractional feedback divider circuit, the first PLL circuit outputting a first tuned frequency signal and a first plurality of integer divider circuits coupled to receive the first tuned frequency signal from the first PLL circuit and each of the first plurality of integer-only post-PLL divider circuits to provide one of a plurality of output frequency signals of the frequency synthesizer.

Abstract: An integrated circuit comprising, a resonator, a first clock circuit for generating a first clock signal having a first frequency in response to the resonator, a second clock circuit for generating a second clock signal having a second frequency in response to the resonator, wherein the second frequency of the second clock signal is determined by the programmable frequency divider and a clock mode control circuit coupled to the first clock circuit and the second clock circuit, the clock mode control circuit for gradually switching the resonator between the first oscillator circuit and the second oscillator circuit of the integrated circuit, using a shift register based state machine and utilizing the inertia of the resonator to smoothly transition between the two oscillators, to provide a dual mode clock output signal.

Abstract: A load circuit for a crystal oscillator includes a plurality of capacitors and a load control circuit configured to selectively add the capacitors to a load at a terminal of the crystal oscillator responsive to a command signal to provide a non-linear capacitive load at the terminal of the crystal oscillator that compensates for a non-linearity of a frequency versus load capacitance characteristic of the crystal oscillator. The load circuit may include a plurality of switches, respective ones of which are configured to load a terminal of the crystal oscillator with respective ones of the capacitors, and control circuit configured to control the plurality of switches to load the terminal of the crystal oscillator responsive to a binary command signal such that respective single ones of the switches operates in response to respective quantum changes a binary command signal over an operating range of the binary command signal.