An analog-to-digital converter (ADC) includes: a set of comparators configured to provide comparison results based on an analog signal and respective reference thresholds for comparators of the set of comparators; digitization circuitry configured to provide a digital output code based on the comparison results and a mapping; and calibration circuitry. The calibration circuitry is configured to: receive the comparison results; determine if the analog signal is proximate to one of the respective reference thresholds based on the comparison results; in response to determining the analog signal is proximate to one of the respective reference thresholds, receive ADC values based on different pseudorandom binary sequence (PRBS) values being applied to the analog signal; determine an offset error based on the ADC values; and provide a comparator input offset calibration signal at a calibration circuitry output if the estimated offset error is greater than an offset error threshold.

A variable resistor may be coupled between a reference voltage source and components of an integrated circuit to reduce issues relating to thermal noise from a reference voltage signal generated by the reference voltage source. The variable resistor may be set to a low level during a first time period and a high level during a second time period, in which the time periods correspond to a sampling period of a switched-capacitor circuit. The low resistance time period may allow quick settling of an input reference voltage signal, whereas the high resistance time period may reduce a bandwidth of noise on a sampling capacitor coupled to the reference voltage signal. The variable resistor and switched-capacitor network may be used in an analog-to-digital converter (ADC), such as in audio circuits.

A digital to time converter (DTC) system is disclosed. The DTC system comprises a DTC circuit configured to generate a DTC output clock signal at a DTC output frequency, based on a DTC code. In some embodiments, the DTC system further comprises a calibration circuit comprising a period error determination circuit configured to determine a plurality of period errors respectively associated with a plurality consecutive edges of the DTC output clock signal. In some embodiments, each period error of the plurality of period errors comprises a difference in a measured time period between two consecutive edges of the DTC output clock signal from a predefined time period. In some embodiments, the calibration circuit further comprises an integral non-linearity (INL) correction circuit configured to determine a correction to be applied to the DTC code based on a subset of the determined period errors.

A pipeline ADC comprising an ADC segment and a digital backend coupled to the ADC segment. In some examples the ADC is configured to receive an analog signal, generate a first partial digital code representing a first sample of the analog signal, and generate a second partial digital code representing a second sample of the analog signal. In some examples the digital backend is configured to receive the first and second partial digital codes from the ADC segment, generate a combined digital code based at least partially on the first and second partial digital codes, determine a gain error of the ADC segment based at least partially on a first correlation of a PRBS with a difference between the first and second partial digital codes, and apply a first correction to the combined digital code based at least partially on the gain error of the ADC segment.

A dither is an uncorrelated signal, usually pseudo-random noise injected into the input of an ADC such that a given input value of the wanted signal becomes spread over a plurality of codes. This reduces the effect of DNL and also smooths the integral non-linearity (INL) response of the ADC. The advantages of introducing dither could be obtained without having to perturb the signal input to the ADC. This avoids the introduction of additional components in the ADC. The dither can be applied to the components used to form a residue of the ADC stage within a pipelined converter. For example, a dither can be applied solely to a DAC part or different dithers can be applied to a ADC and DAC parts respectively. This allows greater flexibility of linearization of the ADC response and the formation of an analog residue by the DAC.

Analog circuits are often non-linear, and the non-linearities can hurt performance. Designers would trade off power consumption to achieve better linearity. An efficient and effective calibration technique can address the non-linearities and reduce the overall power consumption. A dither signal injected to the analog circuit can be used to expose the non-linear behavior in the digital domain. To detect the non-linearities, a counting approach is applied to isolate non-linearities independent of the input distribution. The approach is superior to and different from other approaches in many ways.

A method and system for data conversion includes an analog noise generator to generate a random, non-deterministic, analog noise signal. An adder adds the analog noise signal to an analog RF signal to produce a dithered analog signal. A first quantizer converts the analog noise signal to digital to produce a digital noise signal. A second quantizer converts the dithered analog signal to a digital equivalent signal. A digital dither adjustment module removes amplitude measurements of the digital noise signal from the digital equivalent signal to obtain a linearized digital representation of the analog RF signal.

Techniques to use reservoir capacitors in ADC to supply most of the charge to bit-trial capacitors as bit-trials are performed. An accurate reference voltage source, e.g., a reference buffer circuit, only needs to supply the difference, e.g., an inaccuracy, in the charge supplied by the reservoir capacitors. Instead of having to resettle for each bit-trial, the accurate reference voltage source has only to deliver the initial charge to the reservoir capacitors during acquisition and once more when the ADC is ready to sample onto the residue amplifier. These techniques can ease the demands on the reference buffer circuit and requirement of external decoupling capacitors, for example.

Techniques that allow application of noise-shaped dither without applying dither at sampling, resulting in the analog-to-digital converter (ADC) circuit advantageously being balanced during acquisition. Balancing the ADC circuit at acquisition can reduce the risk of sampling digital interferences that can couple in through the references or substrates.

A circuit device includes a code data generation circuit that generates code data which changes with time, and a successive approximation type A/D conversion circuit that performs code shift based on the code data and performs A/D conversion of an input signal. The code data generation circuit generates error data of which a frequency characteristic has a shaping characteristic and converts the error data into the code data.