A phase interpolator includes a decoder, a digital-to-analog converter (DAC), and a phase mixer. The decoder generates first and second thermometer codes and a selection signal based on a code. The DAC includes unit cells, determines two of weight signals as first and second target weight signals based on the selection signal, and adjusts a current of the first and second target weight signals by controlling the unit cells based on the first and second thermometer codes and the selection signal. The phase mixer determines two of input clock signals as first and second target clock signals and generates an output clock signal based on the first and second target weight signals and the first and second target clock signals. A phase of the output clock signal is between phases of the first and second target clock signals. The unit cells include different first and second unit cells.

A PAM-4 receiver with jitter compensation clock and data recovery is provided. The receiver includes a first-order delay-locked loop (DLL) which employs a bang-bang phase detector (BBPD) and a voltage-controlled delay line (VCDL) circuit supporting 40 MHz jitter tracking bandwidth and static phase skew elimination. A second-order wideband phase-locked loop (WBPLL) using the ¼-rate reference clock provides multi-phase clock generation with low input-to-output latency. To suppress the consequent jitter transfer, a jitter compensation circuit (JCC) acquires the jitter transfer amplitude and frequency information by detecting the DLL loop filter voltage (VLF(s)) signal, and generates an inverted loop filter voltage signal, denoted as VLF.sub.INV(s). The VLF.sub.INV(s) modulates a group of complementary VCDLs (C-VCDLs) to attenuate the jitter transfer on both recovered clock and data. With the provided receiver, a jitter compensation ratio up to 60% can be supported from DC to 4 MHz, with a −3-dB corner frequency of 40 MHz.

A time to digital circuit may provide a time measurement of an event, or a time measurement of a duration between multiple events. Various electronic devices may include one or more time to digital circuits. A time to digital circuit may include circuitry to use Thermometer Code for measuring the duration of the time. For example, the time to digital circuit may generate alternating signals using a ring oscillator when receiving an indication of an event. Moreover, the time to digital circuit may convert the alternating signals to a consistent signal with only one transition between high and low signals in multiple consecutive signals. Furthermore, the time to digital circuit may correct erroneous signal values of the consistent signals when multiple transitions between high and low signals in multiple consecutive signals occurs.

A dynamic element method includes the following operations: summing up most significant bits of a digital code in a previous period and a pointer signal in the previous period, in order to generate a first signal; outputting the first signal to be an adjusted pointer signal according to a clock signal; and decoding the adjusted pointer signal to be control signals, in which the control signals are configured to set corresponding relations of components of a first digital to analog converter circuits and the most significant bits, in order to utilize the components to convert the most significant bits.

A phase interpolator includes a decoder, a digital-to-analog converter (DAC), and a phase mixer. The decoder generates first and second thermometer codes and a selection signal based on a code. The DAC includes unit cells, determines two of weight signals as first and second target weight signals based on the selection signal, and adjusts a current of the first and second target weight signals by controlling the unit cells based on the first and second thermometer codes and the selection signal. The phase mixer determines two of input clock signals as first and second target clock signals and generates an output clock signal based on the first and second target weight signals and the first and second target clock signals. A phase of the output clock signal is between phases of the first and second target clock signals. The unit cells include different first and second unit cells.

A quad signal generator circuit generates four 2.sup.N-1 bit control signals in response to a 2.sup.N-1 bit thermometer coded signal. A digital-to-analog converter (DAC) circuit has 2.sup.N-1 unit DAC elements, with each unit DAC element including four switching circuits controlled by corresponding bits of the four 2.sup.N-1 bit control signals. Outputs of the 2.sup.N-1 unit DAC elements are summed to generate an analog output signal. The quad signal generator circuit controls a time delay applied to clock signals relative to the 2.sup.N-1 bit thermometer coded signal and a time delay applied to the 2.sup.N-1 bit thermometer coded signal relative to the delayed clock signals in logically generating the four 2.sup.N-1 bit control signals. The analog output signal may be a feedback signal in a sigma-delta analog-to-digital converter (ADC) circuit that includes a multi-bit quantization circuit operating to quantize a filtered loop signal to generate the 2.sup.N-1 bit thermometer coded signal.

The disclosure describes an implementation of a combinational thermometric-R2R that includes a thermometric DAC circuit to output the coarse output steps, an R2R circuit to control the fine output steps, and a resistor in series with the thermometric and R2R circuits. The techniques of this disclosure implement a fine resolution DAC, on the order of two nanoamps per bit, that operates at low current, yet maintains monotonicity throughout the DAC output range.

A quad signal generator circuit generates four 2.sup.N−1 bit control signals in response to a sampling clock and a 2.sup.N−1 bit thermometer coded signal. A digital-to-analog converter (DAC) circuit has 2.sup.N−1 unit resistor elements, with each unit resistor element including four switching circuits controlled by corresponding bits of the four 2.sup.N−1 bit control signals. Outputs of the 2.sup.N−1 unit resistor elements are summed to generate an analog output signal. The quad signal generator circuit controls generation of the four 2.sup.N−1 bit control signals such that all logic states of bits of the four 2.sup.N−1 bit control signals remain constant for at least a duration of one cycle of the sampling clock. The analog output signal may be a feedback signal in a sigma-delta analog-to-digital converter (ADC) circuit that includes a multi-bit quantization circuit operating to quantize a filtered loop signal to generate the 2.sup.N−1 bit thermometer coded signal.

Disclosed are an analog-to-digital converter error shaping circuit and a successive approximation analog-to-digital converter. The analog-to-digital converter error shaping circuit includes a decentralized capacitor array, a data weighted average module, a mismatch error shaping module, a control logic generation circuit, a digital filter and a decimator. The decentralized capacitor array includes two symmetrically arranged capacitor array units, each capacitor array unit includes a first sub-capacitor array of a high segment bit and a second sub-capacitor array of a low segment bit. The data weighted average module is configured to eliminate correlation between the first sub-capacitor array and an input signal, and the mismatch error shaping module is configured to eliminate correlation between the second sub-capacitor array and the input signal.

A quad signal generator circuit generates four 2.sup.N−1 bit control signals in response to a sampling clock and a 2.sup.N−1 bit thermometer coded signal. A digital-to-analog converter (DAC) circuit has 2.sup.N−1 unit resistor elements, with each unit resistor element including four switching circuits controlled by corresponding bits of the four 2.sup.N−1 bit control signals. Outputs of the 2.sup.N−1 unit resistor elements are summed to generate an analog output signal. The quad signal generator circuit controls generation of the four 2.sup.N−1 bit control signals such that all logic states of bits of the four 2.sup.N−1 bit control signals remain constant for at least a duration of one cycle of the sampling clock. The analog output signal may be a feedback signal in a sigma-delta analog-to-digital converter (ADC) circuit that includes a multi-bit quantization circuit operating to quantize a filtered loop signal to generate the 2.sup.N−1 bit thermometer coded signal.