Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

A PVT-independent fixed delay circuit includes a circuit structure that has a current generator and a multi-level inverter-based time delay unit. The inverter-based time delay unit has at least two NMOS transistors M5, M6, and at least two PMOS transistors M7, M8. The current generator has a circuit structure including at least two NMOS transistors M1, M2, at least two PMOS transistors M3, M4 and a resistor R.sub.S.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

A temperature-compensated ring oscillator circuit includes a plurality of series-coupled inverters in a ring configuration and a plurality of capacitors. Each capacitor couples to an output of a corresponding inverter. A first transistor is included that comprises a first control input and first and second current terminals. The second current terminal couples to the power supply terminal of each inverter. A second transistor is included that comprises a second control input and third and fourth current terminals. A resistor couples to the fourth current terminal of the second transistor at a first node. An amplifier includes a first amplifier input, a second amplifier input, and an amplifier output. The amplifier output couples to the first and second control inputs. The first amplifier input couples to the second current terminal of the first transistor and the second amplifier input couples to the first node.

Provided is a semiconductor device including a target circuit, a monitoring circuit, and a voltage controller. The target circuit includes a transistor. The monitoring circuit is configured to measure a temperature of the target circuit or measure a delay time between an input and an output of the target circuit. The voltage controller is configured to adjust a driving voltage for driving the target circuit or a back-bias voltage for adjusting a threshold voltage of the transistor by referring to at least one of the temperature and the delay time. As the temperature increases, the delay time decreases.

An integrated circuit may include path delay calibration circuitry. The calibration circuitry may be configured to calibrate respective delay paths so that data and control signals travelling through the respective delay paths experience proper propagation delays during normal user operation. The calibration circuitry may include a high frequency error calibration circuit, a monitoring circuit, and a calibration processing circuit. The high frequency error calibration circuit may be used to compute first calibration settings that take into account jitter and process variations. The monitoring circuit may be used to measure a proxy parameter of interest. The processing circuit may be used to compute an offset based at least partly on the measured value of the proxy parameter. The offset may be applied to the first calibration settings to obtain second calibration settings, which can be used to configure the respective delay paths.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.