A voltage-mode transmitter includes a calibration circuit having a replica circuit. By adjusting a feedback voltage driving a gate of a replica transistor in the replica circuit so that an impedance of the replica circuit matches an impedance of a variable resistor, the calibration circuit calibrates an output impedance of a single slice driver.

An apparatus comprises a digitally controlled circuit having a variable capacitance and a controller configured to adjust a magnitude of the variable capacitance of the digitally controlled circuit. The digitally controlled circuit comprises a plurality of gain elements, the plurality of gain elements comprising one or more positive voltage-to-frequency gain elements and one or more negative voltage-to-frequency gain elements. The controller is configured to adjust the magnitude of the capacitance by adjusting the gain provided by respective ones of the gain elements in an alternating sequence of the positive voltage-to-frequency gain elements and the negative voltage-to-frequency gain elements.

An apparatus includes circuitry and an oscillator circuit that may be configured to generate a clock signal dependent upon a control signal. The circuitry may be configured to perform a frequency measurement of the clock signal. In response to a determination that the frequency of the clock signal is greater than a first threshold, the circuitry may also be configured to perform a phase comparison between a divided clock signal and a reference clock signal, and to adjust a value of the control signal such that the adjusted value depends upon a result of the comparison. In response to a determination that the frequency of the clock signal is less than the first threshold, the circuitry may be configured to adjust the value of the control signal such that the adjusted value depends upon a result of the measurement.

A delay lock loop circuit includes a receiver, a delay line circuit, a clock signal generator and a phase detecting circuit. The receiver receives a clock signal and a reference voltage and generates a reference clock signal according to the clock signal and the reference voltage. The delay line circuit is coupled to the receiver and generates a delayed clock signal by delaying the reference clock signal with a delay indication signal. The clock signal generator generates an output clock signal according to the delayed clock signal. The phase detecting circuit generates a detection result by sampling the reference clock signal with a feedback clock signal generated by the output clock signal, and generates the delay indication signal according to a digital value of the detection result.

Performance indicator circuitry is provided for characterizing performance of a phase locked loop (PLL) in a phase path of a polar modulator or polar transmitter that is used to generate a phase modulated RF signal. The PLL includes an oscillator, a high pass path, and a low pass path. The low pass path includes a loop filter. The performance indicator circuitry includes first input circuitry and parameter calculation circuitry. The first input circuitry is configured to input a loop filter signal from the loop filter. The parameter calculation circuitry is configured to compute a value for a performance indicator based on the loop filter signal and control or characterize an aspect of operation of the PLL based on the value.

The invention concerns an apparatus comprising an analog circuit and a digital circuit. The analog circuit may be configured to generate an enable signal in response to (i) a comparison of a width of an up pulse and a pre-determined width and (ii) a comparison of a width of a down pulse and the pre-determined width. The up pulse and the down pulse may be generated in response to a comparison of a feedback signal and a reference signal. The enable signal may be active when both the comparisons are within a pre-determined threshold. The digital circuit may be configured to generate an output signal representing a lock status between (i) the feedback signal and (ii) the reference signal. The lock status may be determined (a) during a decision window based on a number of pulses of the reference signal and (b) when the enable signal is active.

A time-to-digital converter (TDC) circuit includes control logic and a first self-referenced delay cell circuit coupled to the control logic. The first self-referenced delay cell circuit includes: a first bank of capacitors coupled to a first node between a first positive input and a first positive output, where the first bank of capacitors is selectively controlled by a first control signal from the control logic, the first control signal including a first up value corresponding to a first positive threshold; and a second bank of capacitors coupled to a second node between a first negative input and a first negative output, where the second bank of capacitors is selectively controlled by a second control signal from the control logic, the second control signal including a first down value corresponding to a first negative threshold.

A time-to-digital converter (TDC) circuit includes control logic and a first self-referenced delay cell circuit coupled to the control logic. The first self-referenced delay cell circuit includes: a first bank of capacitors coupled to a first node between a first positive input and a first positive output, where the first bank of capacitors is selectively controlled by a first control signal from the control logic, the first control signal including a first up value corresponding to a first positive threshold; and a second bank of capacitors coupled to a second node between a first negative input and a first negative output, where the second bank of capacitors is selectively controlled by a second control signal from the control logic, the second control signal including a first down value corresponding to a first negative threshold.

A clock recovery circuit a first phase-locked loop (PLL) circuit configured to perform a coarse phase fixing operation on a test data signal by using a first reference clock signal, the test data signal having a prescribed pattern, and a second PLL circuit configured to perform a fine phase fixing operation on the test data signal, subsequently to the coarse phase fixing operation. The second PLL circuit may be configured to perform the fine phase fixing operation on the test data signal by selectively using at least two selection reference clock signals among a plurality of second reference clock signals that are delayed from the first reference clock signal by a unit phase, in a training mode, having a phase difference of N times the unit phase, where N is an integer equal to or greater than 2.

A memory controller may include: a request checker identifying memory devices corresponding to requests received from a host among the plurality of memory devices and generating device information on the identified memory devices to perform operations corresponding to the requests; a dummy manager outputting a request for controlling a dummy pulse to be applied to channels of selected memory devices according to the device information among the plurality of channels; and a dummy pulse generator sequentially applying the dummy pulse to the channels coupled to the selected memory devices, based on the request for controlling the dummy pulse. A memory controller may include an idle time monitor outputting an idle time interval of the memory device and a clock signal generator generating a clock signal based on the idle time interval and outputting the clock signal to the memory device through the channel to perform a current operation.