Abstract: A multi-step analog-to-digital converter (ADC). The ADC includes a sampling circuitry, a comparator, a trimming circuitry, and a DC offset actuator. The sampling circuitry is configured to sample an input analog signal. The comparator is for comparing the input analog signal sample or a residual component of the input analog signal sample to a reference value in each step. The trimming circuitry is configured to receive at least one low-order bit (e.g., a least significant bit and/or a second-least significant bit) of digital binary bits of each input analog signal sample and average the low order bit over a plurality of input analog signal samples and generate a control signal for correcting an input DC offset of the comparator based on an average value of the low-order bits. The DC offset actuator is configured to correct the input DC offset of the comparator based on the control signal.

Abstract: A successive approximation register (SAR) analog-to-digital converter (ADC) includes a plurality of differential capacitive digital-to-analog converters (C-DACs), comparators, and an SAR controller. Each differential C-DAC comprises a pair of C-DACs for positive and negative polarities and each C-DAC comprises a capacitor array. A capacitor for each bit position may include a pair of equal-sized capacitors. Each outer comparator is coupled to one of the differential C-DACs and the middle comparator is coupled to a differential output node pair of C-DACs from two differential C-DACs. The SAR controller generates a control signal for the differential C-DACs for each conversion step based on outputs of the comparators. The outputs of the comparators are provided to the differential C-DACs as the control signal without encoding. Single-bit/cycle shorting switches for shorting top plates of capacitors of the C-DACs of same polarity may be closed during a single-bit/cycle conversion.

Abstract: An analog-to-digital converter comprising a plurality of sampling cells. At least one of the plurality of sampling cells comprises a capacitive element coupled to a cell output of the at least one of the plurality of sampling cells, wherein a cell output signal is provided at the cell output. The at least one of the plurality of sampling cells further comprises a first cell input for receiving an input signal to be digitized, and a second cell input for receiving a calibration signal. Additionally, the at least one of the plurality of sampling cells comprises a first switch circuit capable of selectively coupling the first cell input to the capacitive element based on a clock signal, and a second switch circuit capable of selectively coupling the second cell input to the capacitive element, wherein a size of the second switch circuit is smaller than a size of the first switch circuit.

Abstract: An input buffer circuit for an analog-to-digital converter is provided. The input buffer circuit includes a buffer amplifier. The buffer amplifier includes a first input node and a second input node each configured to receive a respective one of a first input signal and a second input signal forming a differential input signal pair for the analog-to-digital converter. The buffer amplifier further includes a first output node and a second output node each configured to output a respective one of a first buffered signal and a second buffered signal. In addition, the input buffer circuit includes feedback circuitry. The feedback circuitry is configured to generate, based on the first buffered signal and the second buffered signal, a first feedback signal and a second feedback signal for mitigating a respective unwanted signal component at the first input node and the second input node related to a limited reverse isolation of the amplifier buffer.

Abstract: A method and system for controlling an analog-to-digital converter (ADC) in an observation path in a transceiver. The transceiver includes a transmit path, a receive path, and an observation path. The observation path includes an analog buffer and an observation ADC. A controller generates a control signal to control sampling events at the observation ADC to activate the observation ADC at combined uniform and non-uniform sampling instants. The controller may also generate a second control signal indicating whether digital data obtained by the observation ADC is valid or not. The digital data generated by the observation ADC at non-uniform sampling instants is indicated as invalid and digital data generated by the observation ADC at uniform sampling instants is indicated as valid. The digital data indicated as invalid may be discarded and the digital data indicated as valid is used for calibration of the transmit path or the receive path.

Abstract: A time-interleaved Analog-to-Digital Converter, ADC, system is provided. The time-inter-leaved ADC system includes time-interleaved first and second ADC circuits and a switching circuit. The switching circuit is configured to selectively supply an analog input signal for digitization to at least one of the first ADC circuit, the second ADC circuit or ground, and to selectively supply an analog calibration signal to at least one of the first ADC circuit, the second ADC circuit or ground. Further, the time-interleaved ADC system includes an output circuit configured to selectively generate, based on least one of a first digital signal output by the first ADC circuit and a second digital signal output by the second ADC circuit, a digital output signal.

Abstract: A time-interleaved Analog-to-Digital Converter, ADC, system is provided. The time-inter- leaved ADC system includes time-interleaved first and second ADC circuits and a switching circuit. The switching circuit is configured to selectively supply an analog input signal for digitization to at least one of the first ADC circuit, the second ADC circuit or ground, and to selectively supply an analog calibration signal to at least one of the first ADC circuit, the second ADC circuit or ground. Further, the time-interleaved ADC system includes an output circuit configured to selectively generate, based on least one of a first digital signal output by the first ADC circuit and a second digital signal output by the second ADC circuit, a digital output signal.

Abstract: A n-bit Successive Approximation Register Analog-to-Digital Converter, SAR ADC, is provided. The SAR ADC comprises a respective plurality of sampling cells for each bit of the n-bit of the SAR ADC. Each sampling cell comprises a capacitive element coupled to a cell output of the sampling cell in order to provide a cell output signal. Further, each sampling cell comprises a first cell input for receiving a first signal, and a first switch circuit capable of selectively coupling the first cell input to the capacitive element. Each cell additionally comprises a second cell input for receiving a second signal, and a third cell input for receiving a third signal. The third signal exhibits opposite polarity compared to the second signal. Each sampling cell comprises a second switch circuit capable of selectively coupling one of the second cell input and the third cell input to the capacitive element. The SAR ADC further comprises at least one comparator circuit coupled to the sampling cells.

Abstract: An active filter and an analog-to-digital converter (ADC) configured to suppress out-of-band peaking. An active filter may include an active device configured to provide a power gain to an input signal, a feedback network configured to connect an output of the active device to an input of the active device, and an input impedance network configured to couple the input signal to the input of the active device. A combination of the feedback network and the input impedance network is configured to provide frequency response properties of the active filter such that a frequency domain signal transfer function of the active filter has a constant in numerator.

Abstract: A n-bit Successive Approximation Register Analog-to-Digital Converter, SAR ADC, is provided. The SAR ADC comprises a respective plurality of sampling cells for each bit of the n-bit of the SAR ADC. Each sampling cell comprises a capacitive element coupled to a cell output of the sampling cell in order to provide a cell output signal. Further, each sampling cell comprises a first cell input for receiving a first signal, and a first switch circuit capable of selectively coupling the first cell input to the capacitive element. Each cell additionally comprises a second cell input for receiving a second signal, and a third cell input for receiving a third signal. The third signal exhibits opposite polarity compared to the second signal. Each sampling cell comprises a second switch circuit capable of selectively coupling one of the second cell input and the third cell input to the capacitive element. The SAR ADC further comprises at least one comparator circuit coupled to the sampling cells.

Abstract: An apparatus and method for analog-to-digital conversion. The apparatus includes a first analog-to-digital converter (ADC), a second ADC, and a calibration unit. The first ADC is configured to sample an input analog signal at a first sampling frequency. The second ADC is configured to sample the input analog signal at a second sampling frequency. The second sampling frequency is a fraction of the first sampling frequency. The calibration unit is configured to correct a distortion incurred in an output of the first ADC based on an output of the second ADC. The first ADC may be a time-interleaved ADC. The second ADC may be an extra sub-ADC of the time-interleaved ADC. The second ADC may be configured to sample the input analog signal at random sampling phases. A dithering noise may be added to the input analog signal of the second ADC. The calibration unit may be a non-linear equalizer.

Abstract: An apparatus for calibrating an analog-to-digital converter is provided. The apparatus includes a reference input generation circuit configured to subsequently generate two reference inputs for calibrating the analog-to-digital converter. The two reference inputs both represent ramp waveforms, wherein the ramp waveforms represented by the two reference inputs are different from each other. Further, the apparatus includes a coupling circuit configured to controllably couple an input node of the analog-to-digital converter to either the reference input generation circuit or to a signal node capable of providing an analog input for digitization.

Abstract: An apparatus for calibrating a time-interleaved analog-to-digital converter including a plurality of time-interleaved analog-to-digital converter circuits is provided. The apparatus includes a clock generation circuit configured to generate a plurality of phase shifted clock signals for the plurality of time-interleaved analog-to-digital converter circuits and a reference clock signal. Further, the apparatus includes a reference signal generation circuit configured to generate a reference signal based on the reference clock signal. The reference signal is a square wave signal. The apparatus additionally includes a coupling circuit configured to controllably couple an input node of the time-interleaved analog-to-digital converter to either the reference signal generation circuit or to a signal node capable of providing an analog signal for digitization.

Abstract: An apparatus for calibrating an analog-to-digital converter is provided. The apparatus includes a reference input generation circuit configured to subsequently generate two reference inputs for calibrating the analog-to-digital converter. The two reference inputs both represent ramp waveforms, wherein the ramp waveforms represented by the two reference inputs are different from each other. Further, the apparatus includes a coupling circuit configured to controllably couple an input node of the analog-to-digital converter to either the reference input generation circuit or to a signal node capable of providing an analog input for digitization.

Abstract: An apparatus for calibrating a time-interleaved analog-to-digital converter including a plurality of time-interleaved analog-to-digital converter circuits is provided. The apparatus includes a clock generation circuit configured to generate a plurality of phase shifted clock signals for the plurality of time-interleaved analog-to-digital converter circuits and a reference clock signal. Further, the apparatus includes a reference signal generation circuit configured to generate a reference signal based on the reference clock signal. The reference signal is a square wave signal. The apparatus additionally includes a coupling circuit configured to controllably couple an input node of the time-interleaved analog-to-digital converter to either the reference signal generation circuit or to a signal node capable of providing an analog signal for digitization.

Abstract: A n-bit Successive Approximation Register Analog-to-Digital Converter, SAR ADC, is provided. The SAR ADC comprises a respective plurality of sampling cells for each bit of the n-bit of the SAR ADC. Each sampling cell comprises a capacitive element coupled to a cell output of the sampling cell in order to provide a cell output signal. Further, each sampling cell comprises a first cell input for receiving a first signal, and a first switch circuit capable of selectively coupling the first cell input to the capacitive element. Each cell additionally comprises a second cell input for receiving a second signal, and a third cell input for receiving a third signal. The third signal exhibits opposite polarity compared to the second signal. Each sampling cell comprises a second switch circuit capable of selectively coupling one of the second cell input and the third cell input to the capacitive element. The SAR ADC further comprises at least one comparator circuit coupled to the sampling cells.

Abstract: An apparatus for calibrating a time-interleaved analog-to-digital converter including a plurality of time-interleaved analog-to-digital converter circuits is provided. The apparatus includes an analog signal generation circuit configured to generate an analog calibration signal based on a digital calibration signal representing one or more digital data sequences for calibration. The analog calibration signal is a wideband signal. Further, the apparatus includes a coupling circuit configured to controllably couple an input node of the time-interleaved analog-to-digital converter to either the analog signal generation circuit or to a node capable of providing an analog signal for digitization.