A method and system for calibrating a time-interleaved digital to analog converter (DAC) provides equalization of frequency response misalignments in sub-DACs forming the DAC. In a calibration mode, test signals are applied to an DAC and output amplitudes and phases of are measured. From the measured values, complex values of the gains of the respective sub-DACs. h.sub.m(F) are determined and a specified target frequency response T(F) for a tandem connection equalizer-DAC is determined. For each of a plurality of test frequencies, complex values of equalizer gains Eq.sub.m are determined from Eq.sub.m(F)=T(F)/h.sub.m(F), to form equalizing frequency responses. Sets of equalizing coefficients C.sub.m(p) pursuant to discrete Fourier transforms on Eq.sub.m(F). In an operation mode, a digital input signal is transformed input into an equalized digital signal E(n) through use of the sets of equalizing coefficients C.sub.m(p).

According to an embodiment, a digital-to-analog converter may be provided. The digital-to-analog converter may include a resistive ladder network including a plurality of paths corresponding to bit currents, respectively. The digital-to-analog converter may include a switching circuit configured to include a plurality of weighted elements respectively coupled to the paths. The digital-to-analog converter may include a reference voltage setting circuit coupled to the weighted elements and the paths, and configured to minimize a variation of threshold voltages of the weighted elements.

Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals. A multiplier may be configured to cancel the blocker signal utilizing the determined complex coupling coefficients.

A successive approximation register, SAR, analog-to-digital converter, ADC, (400) is described. The SAR ADC (400) includes: a track and hold circuit (414) configured to sample an analog input signal (410); a comparator (416) coupled to the track and hold circuit and configured to compare the sampled analog input signal (410) with a DAC (444) output voltage; and a feedback path (422) that comprises a digital-to-analog converter, DAC, (444) configured to generate the reference voltage that approximates the input analog signal (410). The SAR ADC (400) further includes a dither circuit (468) coupled to or located in the feedback path (422) and arranged to add a dither signal at an input of the DAC (444) in a first time period and subtract the dither signal from the output digital signal routed via the feedback path (422) and input of the DAC (444) in a second time period during a conversion phase of the SAR ADC (400).

To provide a variable gain amplifier capable of correcting a DC offset voltage through simpler control even when a gain thereof is changed. A differential output type variable gain amplifier is equipped with a first voltage correction unit coupled to a preceding stage of a variable gain amplifier circuit and for outputting a first correction voltage to correct a potential difference generated between a first conductor provided with a first input resistor and a second conductor provided with a second input resistor, and a second voltage correction unit coupled to a subsequent stage of the variable gain amplifier circuit and for correcting a differential output. A control unit is configured to control the first correction voltage and a correction amount of a potential difference by the second voltage correction unit and thereby attenuate a DC offset voltage included in the differential output.

Digital to analog converter architectures are disclosed that enable the binary scaling of transistor sized to be replaced by transistors of substantially the same size. This significantly reduced the size of the Digital to Analog converter on a wafer. As the currents from the lesser bits of the converter may be very small indeed, some of the transistors are operated in a regime where the gate-source voltage applied to the transistor is below the threshold voltage for the device, the threshold voltage generally being regarded as marking the onset of significant conduction through a field effect transistor.

According to an embodiment, a digital-to-analog converter may be provided. The digital-to-analog converter may include a resistive ladder network including a plurality of paths corresponding to bit currents, respectively. The digital-to-analog converter may include a switching circuit configured to include a plurality of weighted elements respectively coupled to the paths. The digital-to-analog converter may include a reference voltage setting circuit coupled to the weighted elements and the paths, and configured to minimize a variation of threshold voltages of the weighted elements.

A converter circuit includes a current interface with a control input, with a current signal output and a current output. The converter circuit includes a micro-processor with a measuring signal input for the digital measuring signal, with a current signal input connected to the current signal output of the current interface, and with a control output connected to the control input of the current interface. The current interface lets the signal current flow through the current output and simultaneously adjust both the amperage to a stationary amperage level corresponding to a control value currently applied to the control input, and to output a sequence of current values at the current signal output. The micro-processor is designed to generate a measuring value sequence on the basis of the digital measuring signal and use it as the basis from which to generate a control value sequence and issue it at the control output as well as to monitor and/or check the current interface using the control value sequence and the current value sequence.

An analog to digital convertor circuit includes an input circuit and a switched capacitor circuit. The input circuit is configured to selectively drain a first current from a first node or drain a second current from a second node according to a first bit and a second bit that have opposite logic values. The switched capacitor circuit is configured to compensate a capacitance value of one of the first node and the second node according to the first bit and the second bit.

The present technology relates to an image pickup device and an electronic apparatus capable of preventing degradation of the picture quality. A plurality of current sources can be selectively connected to an output terminal for outputting a reference signal having a level that varies, and a plurality of terminating resistors are connected to the output terminal. The terminating resistors that are to supply current of current sources that are connected to the output terminal are connected by a plurality of switches, and current of current sources that are not connected to the output terminal is supplied to the switches. The present technology can be applied, for example, to image pickup devices that perform AD conversion using a reference signal and so forth.