Abstract: Systems, devices, and methods are described herein for aligning a phase of a ring oscillator and removing jitter. An oscillator includes a resistor bank array, an operational amplifier, a first and second transistor, and a realignment circuit. The resistor bank array has a plurality of resistors configured to generate a first signal. The operational amplifier is coupled to a PLL circuit and is configured to compare a voltage of the PLL circuit with a voltage of the resistor bank array. The first transistor is coupled between the operational amplifier and a ring oscillator. The first transistor is configured to generate a second signal to control a frequency of the ring oscillator during a realignment state. The realignment circuit is coupled to the first transistor and the ring oscillator. The realignment circuit is configured to generate a realignment signal to align the ring oscillator with a first clock signal.

Abstract: An apparatus and method for providing a phase noise built-in self test (BIST) circuit are disclosed herein. In some embodiments, a method and apparatus for forming a multi-stage noise shaping (MASH) type high-order delta sigma (??) time-to-digital converter (TDC) are disclosed. In some embodiments, an apparatus includes a plurality of first-order ?? TDCs formed in an integrated circuit (IC) chip, wherein each of the first-order ?? TDCs are connected to one another in a MASH type configuration to provide the MASH type high-order ?? TDC, wherein the MASH type high-order ?? TDC is configured to measure the phase noise of a device under text (DUT).

Abstract: Systems and methods are provided for a phase locked loop. A phase/frequency detector is configured to receive a reference signal and a feedback signal. A charge pump is configured to receive outputs from the phase/frequency detector and to generate pulses. An oscillator is configured to generate an output waveform based on the charge pump pulses. A realignment path is configured to generate a clock realignment signal that is provided to the oscillator based on the outputs from the phase/frequency detector.

Abstract: Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.

Abstract: A frequency divider circuit includes a counter configured to generate a counter signal responsive to a frequency of a clock signal and a frequency ratio, and a compensation circuit coupled to the counter, and configured to generate an output signal. The output signal has a frequency equal to the frequency of the clock signal divided by a frequency ratio, and a duty cycle lower than 50% and greater than 1/r, where r is the frequency ratio.

Abstract: A device includes a phase detector circuit, a charge pump circuit, a sample and hold circuit, a comparator, and a controller. The phase detector circuit detects a clock skew between a reference signal and an input signal. The charge pump circuit translates the clock skew into a voltage. A sample and hold circuit samples the voltage, at a first time, and maintain the sampled voltage until a second time. The comparator (i) detects a loop gain associated with the input signal based on the sampled voltage and the voltage at the second time and (ii) outputs a loop gain signal for adjustment of the input signal. The controller is coupled to the phase detector, the comparator, and the sample and hold circuit. The controller generates a plurality of control signals for automatically controlling operation of the phase detector, the comparator, and the sample and hold circuit.

Abstract: The present disclosure describes an example method for cell placement in an integrated circuit (IC) layout design. The method includes defining a layout unit for a circuit implementation and arranging multiple layout units into a layout cell. The method also includes editing the layout cell to connect a first set of the layout units to be representative of the circuit implementation and to connect a second set of the layout units to be representative of a non-functional circuit. Further, the method includes inserting one or more dummy fill structures in areas of the layout cell unoccupied by the first and second sets of layout units.

Abstract: An apparatus and method for providing a phase noise built-in self test (BIST) circuit are disclosed herein. In some embodiments, a method and apparatus for forming a multi-stage noise shaping (MASH) type high-order delta sigma (??) time-to-digital converter (TDC) are disclosed. In some embodiments, an apparatus includes a plurality of first-order ?? TDCs formed in an integrated circuit (IC) chip, wherein each of the first-order ?? TDCs are connected to one another in a MASH type configuration to provide the MASH type high-order ?? TDC, wherein the MASH type high-order ?? TDC is configured to measure the phase noise of a device under text (DUT).

Abstract: A circuit includes a period calculator and a pulse width calculator. The period calculator is configured for receiving a first predetermined digital code and a second predetermined digital code, and for calculating a first calculated period value according to the first predetermined digital code, and calculating a second calculated period value according to the second predetermined digital code. The first predetermined digital code has a first predetermined period value, and the second predetermined digital code has a second predetermined period value. The pulse width calculator is configured for receiving a predetermined pulse width, and calculating a first pulse width code corresponding to the predetermined pulse width according to the first predetermined period value, the second predetermined period value, the first calculated period value, the second calculated period value and the predetermined pulse width.

Abstract: A controlling circuit for ring oscillator is provided. A first transistor and a second transistor of a first conductive type are coupled in series and between a node and a first power source. A third transistor and a fourth transistor of a second conductive type are coupled in parallel and between the node and a second power source. The node is coupled to an input of a delay chain of the ring oscillator. The second and third transistors are coupled in series. Gates of the second and third transistors are configured to receive an output signal of the delay chain. When the first transistor is turned off and the fourth transistor is turned on, the node is pulled to a first logic level from a second logic level in order to align a phase of a waveform of the ring oscillator.

Abstract: A method and apparatus of generating precision phase skews is disclosed. In some embodiments, a phase skew generator includes: a charge pump having a first mode of operation and a second mode of operation, wherein the first mode of operation provides a first current path during a first time period, and the second mode of operation provides a second current path during a second time period following the first time period; a sample and hold circuit, coupled to a capacitor, and configured to sample a voltage level of the capacitor at predetermined times and provide an output voltage during a third time period following the second time period; and a voltage controlled delay line, coupled to the sample and hold circuit, and having M delay line stages each configured to output a signal having a phase skew offset with respect to preceding or succeeding signal.

Abstract: A duty cycle adjustment system includes a time-to-digital converter to generate a plurality of time-to-digital codes from an input signal, a duty cycle index generator to compute a duty cycle of the input signal based upon the plurality of time-to-digital codes, and assign a duty cycle index based upon the computed duty cycle, an input phase assignment generator to generate a first output and a second output based upon the duty cycle index, a first delay line to delay the first output to generate a third output, and a duty cycle generator to adjust the duty cycle of the input signal based upon the third output and the second output.

Abstract: The present disclosure describes an example method for cell placement in an integrated circuit (IC) layout design. The method includes defining a layout unit for a circuit implementation and arranging multiple layout units into a layout cell. The method also includes editing the layout cell to connect a first set of the layout units to be representative of the circuit implementation and to connect a second set of the layout units to be representative of a non-functional circuit. Further, the method includes inserting one or more dummy fill structures in areas of the layout cell unoccupied by the first and second sets of layout units.

Abstract: A system, a method and a built-in phase noise measurement apparatus are introduced. The built-in phase noise measurement apparatus includes a first DLL and a TDC, in which the first DLL circuit controls a delay of a first signal to generate a second signal based on a control code, tune the control code until a phase of the second signal is aligned to a phase of a reference clock signal, and record a value of the control code when the phase of the second signal is aligned to the phase of the reference clock signal. The DLL circuit controls the delay of the first signal based on the value of the control code after the phase of the second signal is aligned to the phase of the reference clock signal. The TDC determines the phase noise of the first signal based on the reference clock signal and the second signal.

Abstract: A circuit includes a period calculator and a pulse width calculator. The period calculator is configured for receiving a first predetermined digital code and a second predetermined digital code, and for calculating a first calculated period value according to the first predetermined digital code, and calculating a second calculated period value according to the second predetermined digital code. The first predetermined digital code has a first predetermined period value, and the second predetermined digital code has a second predetermined period value. The pulse width calculator is configured for receiving a predetermined pulse width, and calculating a first pulse width code corresponding to the predetermined pulse width according to the first predetermined period value, the second predetermined period value, the first calculated period value, the second calculated period value and the predetermined pulse width.

Abstract: A controlling circuit for ring oscillator is provided. First and second transistors of a first conductive type are coupled in series and between a node and a first power source. Third and fourth transistors of a second conductive type are coupled in parallel and between the node and a second power source. The node is coupled to an input of a delay chain of the ring oscillator. The second and third transistors are coupled in series and gates of the second and third transistors are configured to receive an output signal of the delay chain. When the first transistor is turned off and the fourth transistor is turned on, the node is pulled to a first logic level from a second logic level in order to align a phase of a waveform of the ring oscillator.

Abstract: Oscillators and methods for realignment of an oscillator are provided. An oscillator includes an inductor having first and second terminals and a capacitor electrically coupled in parallel to the inductor at the first and second terminals. A first transistor of a first conductivity type is electrically coupled to the first terminal and a voltage source. The first transistor includes a gate configured to receive a first realignment signal. When the first realignment signal is in a realignment state, the first transistor is turned on and a voltage of the first terminal is increased from a low level to a high level in order to align a phase of a waveform of the oscillator.

Abstract: A method and apparatus of generating precision phase skews is disclosed. In some embodiments, a phase skew generator includes: a charge pump having a first mode of operation and a second mode of operation, wherein the first mode of operation provides a first current path during a first time period, and the second mode of operation provides a second current path during a second time period following the first time period, a sample and hold circuit, coupled to a capacitor, and configured to sample a voltage level of the capacitor at predetermined times and provide an output voltage during a third time period following the second time period; and a voltage controlled delay line, coupled to the sample and hold circuit, and having M delay line stages each configured to output a signal having a phase skew offset with respect to preceding or succeeding signal.

Abstract: Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.

Abstract: Phase-locked loops (PLLs) are provided. A PLL includes a voltage-controlled oscillator (VCO), a frequency divider and a track-and-hold charge pump. The VCO is configured to provide an output clock corresponding to a pumping current. The frequency divider is configured to provide a feedback signal according to the output clock. The track-and-hold charge pump is configured to provide the pumping current according to a reference clock and the feedback signal. The track-and-hold charge pump includes a track-and-hold circuit, a pumping switch and a pulse width modulator (PWM). The track-and-hold circuit is coupled to the frequency divider and configured to sample the feedback signal according to the reference clock. The PWM is configured to provide a PWM signal to control the pumping switch according to the reference clock, so as to provide the pumping current corresponding to the sampled feedback signal.