Noise sources in a pipelined ADC circuit can include kT/C sampling noise from a capacitor DAC circuit and residue amplifier sampling noise. The kT/C sampling noise is inversely proportional to the size of the sampling capacitors; the larger sampling capacitors produce less noise. However, larger sampling capacitor can be difficult to drive and physically occupy significant die area. By using the described techniques, the inversely proportional relationship between the sampling noise and the size of the sampling capacitors is no longer true. The size of the sampling capacitors can be greats reduced, which can reduce the die area and reduce the power consumption of the ADC, and the kT/C sampling noise can be canceled using correlated double sampling (CDS) techniques.

An analog to digital converter device includes a capacitor array, a digital logic circuit, and a comparator circuit. The capacitor array includes first capacitors, a capacitor to be calibrated, and compensation capacitors. The digital logic circuit performs a calibration on the capacitor to be calibrated, in order to calibrate a weighed value of the capacitor to be calibrated according to a decision signal, and converts an input signal to bits via the capacitor array after the calibration is performed. The comparator circuit compares a testing signal with a predetermined voltage to generate the decision signal. The testing signal is generated by the first capacitors and the capacitor to be calibrated in response to the calibration. The digital logic circuit further selects at least one of the compensation capacitors, in order to adjust a digital code corresponding to a calibrated weighed value to be an integer expressed by the bits.

A switched capacitor circuit includes an output capacitor, a first transmission switch, a first reference buffer, a second transmission switch, a second reference buffer and a charge compensation circuit. The output capacitor includes a first terminal and a second terminal, wherein the first terminal is coupled to an output terminal of the switched capacitor circuit, and the second terminal is coupled to a reference node. The first transmission switch is coupled to the reference node. The first reference buffer is coupled to the first transmission switch. The second transmission switch is coupled to the reference node. The second reference buffer is coupled to the second transmission switch. The charge compensation circuit is coupled to the reference node.

Disclosed are circuits and methods for a CDAC with capacitive references. Individual reference capacitors can be implemented to provide the reference voltages for each input capacitor in a CDAC. For example, each input capacitor may be allocated a high-reference capacitor and a low-reference capacitor to provide the reference voltage to the respective input capacitor. Each of these reference capacitors is charged along with the input capacitor when the CDAC is configured into a loading configuration, and then used to convert digital data to an analog signal when the CDAC is configured into a conversion configuration. Accordingly, the reference voltage for each input capacitor is provided by a separate power source. This contrasts with current solutions in which the reference voltages for the input capacitors are provided by either a singular high-reference voltage source or low-reference voltage source.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

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. The at least one comparator circuit is configured to output a comparison signal based on the cell output signals of the sampling cells. Additionally, the SAR ADC comprises a calibration circuit configured to supply at least one respective control signal to the respective second switch circuit of the sampling cells for controlling the second switch circuits.

A digital-to-time converter (DTC) converts a digital code into a time delay using a capacitor digital-to-analog converter (CDAC) that functions as a charging capacitor. The DTC includes a switched capacitor voltage-to-current converter for the formation of a charging current (or a discharging current) for charging (or for discharging) the charging capacitor responsive to a triggering clock edge that begins the time delay. A comparator compares a voltage on the charging capacitor to a threshold voltage to determine an end of the time delay.

A digital-to-analog converter includes an array of capacitors, an array of capacitor switches, positive and negative high-bandwidth reference buffers, positive and negative low-bandwidth reference buffers, and a reference-voltage-selection switch. Each capacitor switch electrically couples a respective capacitor to either a positive or a negative reference voltage line. The reference-voltage-selection switch electrically couples the positive and negative reference voltage lines to either positive and negative high-bandwidth voltages or to positive and negative low-bandwidth voltages. The positive and negative high-bandwidth voltages are produced by the positive and negative high-bandwidth reference buffers. The positive and negative low-bandwidth voltages are produced by the positive and negative low-bandwidth reference buffers.

An analog-to-digital converter includes a first converter stage, a second converter stage coupled to the first converter stage to quantize a residue signal of the first converter stage, and an inter-stage converter disposed between the first and second converter stages. The inter-stage converter is configured to convert between a first domain and a second domain. The inter-stage converter is configured to process the residue signal of the first converter stage such that a range of the residue signal matches a full scale of the second converter stage.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.