Abstract: A fringe capacitor with a shielded the top capacitor plate is formed in multiple interconnect layers to include a first plate having a first defined finger structure located in one or more middle interconnect layers to form a top capacitor plate; a set of second plates located in the middle interconnect layer(s) and bottom and top interconnect layers that are connected to form a bottom capacitor plate which includes a second plate in the middle interconnect layer(s) having defined finger structures that are interleaved with the first defined finger structure of the top capacitor plate to vertically and horizontally sandwich the top capacitor plate; and a set of shield layers formed to surround and shield the top capacitor plate on lateral sides, where the set of shield layers are connected to a reference voltage, thereby shielding the top capacitor plate from parasitic capacitance.

Abstract: Time-interleaved analog-to-digital converters (ADCs) and related methods are disclosed that are based upon multiplying digital-to-analog converters (MDACs). For one ADC embodiment, a sample-and-hold circuit receives an input signal and outputs a voltage that represents the input signal. An MDAC receives the voltage, outputs an N-bit digital value, and outputs a current that represents the voltage. A phased current generator receives the current and outputs time-interleaved currents that are based upon the current. An array of sub-ADCs receive the time-interleaved currents, and each sub-ADC outputs a digital value. The digital values from the array of sub-ADCs are then combined and to output an M-bit digital value. The N-bit digital value and the M-bit digital value provide a digital conversion output for the ADC.

Abstract: A switched-capacitor gain stage circuit and method include an amplifier connected to an input sampling circuit with sampling switched capacitors for coupling an input voltage and a first or second reference voltage to one or more central nodes during a sampling phase and for coupling the one or more central nodes to an amplifier input during a gain phase, wherein a reference loading circuit uses a plurality of sampling switched capacitors connected in a switching configuration to selectively couple a first reference voltage and/or a second reference voltage to the central node by pre-charging the plurality of sampling switched capacitors with the first and second reference voltages during the sampling phase, and by coupling each of the first and second reference voltages to at least one of the plurality of sampling switched capacitors when connected to the central node during the gain phase.

Abstract: Current controlled multiplying digital-to-analog converters (MDACs) and related methods are disclosed for time-interleaved analog-to-digital converters (ADCs). For one embodiment, a circuit includes an MDAC having an amplifier that converts a voltage to an output current, a variable load that is dependent upon a digital value and that controls the output current from the amplifier, and an array of comparators that receive the voltage and output the digital value to the variable load. The digital value represents at least a portion of a digital conversion of the voltage. Further, the circuit can include a phased current generator that receives the output current and generates time-interleaved currents where each time-interleaved current is a sampled copy of the output current.

Abstract: Digital calibration systems and related methods are disclosed for multi-stage analog-to-digital converters (ADCs). For one embodiment, a multi-stage ADC includes an initial ADC, an additional ADC, and calibration logic. The initial ADC generates an output signal and N-bit digital values that are based upon an input signal. The additional ADC receives the output signal from the initial ADC and generates M-bit digital values that are based upon the output signal. The calibration logic receives the N-bit digital values and the M-bit digital values and generates correction values. The correction values are based upon differences between maximum values and minimum values for M-bit digital values associated with different regions determined by the N-bit digital values. Digital conversion outputs for the multi-stage ADC are provided as combinations of the N-bit digital values and the M-bit digital values corrected with the correction values.

Abstract: A switched-capacitor gain stage circuit and method include an amplifier connected to an input sampling circuit with sampling switched capacitors for coupling an input voltage and a first or second reference voltage to one or more central nodes during a sampling phase and for coupling the one or more central nodes to an amplifier input during a gain phase, wherein a reference loading circuit uses a plurality of sampling switched capacitors connected in a switching configuration to selectively couple a first reference voltage and/or a second reference voltage to the central node by pre-charging the plurality of sampling switched capacitors with the first and second reference voltages during the sampling phase, and by coupling each of the first and second reference voltages to at least one of the plurality of sampling switched capacitors when connected to the central node during the gain phase.

Abstract: A fringe capacitor with a shielded the top capacitor plate is formed in multiple interconnect layers to include a first plate having a first defined finger structure located in one or more middle interconnect layers to form a top capacitor plate; a set of second plates located in the middle interconnect layer(s) and bottom and top interconnect layers that are connected to form a bottom capacitor plate which includes a second plate in the middle interconnect layer(s) having defined finger structures that are interleaved with the first defined finger structure of the top capacitor plate to vertically and horizontally sandwich the top capacitor plate; and a set of shield layers formed to surround and shield the top capacitor plate on lateral sides, where the set of shield layers are connected to a reference voltage, thereby shielding the top capacitor plate from parasitic capacitance.

Abstract: A method for Signal-to-Noise and Distortion Ratio (SNDR) improvement through optimal Digital-to-Analog-Converter (DAC) element selection includes randomizing an order of a plurality of unit elements of a DAC, wherein each of the unit elements is controlled by a respective one of a plurality of digital inputs of the DAC. The plurality of digital inputs is sequentially asserted over at least a subset of a full set of the digital inputs to generate a plurality of analog values of an output of the DAC. A first SNDR of the DAC is measured from the plurality of analog values. A maximum SNDR, corresponding to an optimal order, is determined from the first SNDR and at least one previously measured SNDR. The optimal order of the unit elements of the DAC is stored in a memory to define connections between the digital inputs and the respective unit elements based on the optimal order.

Abstract: A switched-capacitor gain stage circuit and method include an amplifier connected to an input sampling circuit with sampling switched capacitors for coupling an input voltage and a first or second reference voltage to one or more central nodes during a sampling phase and for coupling the one or more central nodes to an amplifier input during a gain phase, wherein a common-mode reference voltage generation circuit uses one or more additional sampling switched capacitors to selectively couple the first and second reference voltages to the amplifier input during the gain phase when the input voltage is between the high and low threshold voltages using a switching configuration of switches that are controllable to connect the sampling switched capacitors to the one or more central nodes in the sampling phase, and to connect the amplifier output in feedback to the input sampling circuit in the gain phase while simultaneously connecting the one or more central nodes to the first amplifier input.

Abstract: A digital to analog converter (DAC) circuit includes pulse generator circuit for generating voltage pulses having a predetermined length and shape. The voltage pulses are used to control the generation of current pulses generated by a voltage to current converter. The voltage to current converter includes a set of switchable resistors where the resistance value provided by the set is dependent upon a digital value of a digital signal. In some embodiments, the current amplitude of the current pulses is dependent upon the resistance value and is indicative of the digital value.

Abstract: A digital to analog converter convert digital data in binary format to thermometer bit vectors. A first set of the thermometer bit vectors corresponds to most significant bits of the digital data and a second set of the thermometer bit vectors corresponds to least significant bits of the digital data. Connections of first current sources corresponding to the first set of the thermometer bit vectors and second current sources corresponding to the second set of the thermometer bit vectors are dynamically and randomly alternated to a first output line and a second output line. Calibration current is applied to the second current sources so a total current of the second current sources and the calibration current is within a predetermined range of an average current of the first current sources.

Abstract: A multi-rate cascaded continuous-time analog-to-digital converter has a plurality of sigma-delta modulator stages and includes first and second continuous-time sigma-delta modulators, and a summation element. The first continuous-time sigma-delta modulator operates at a first sampling rate. The second continuous-time sigma-delta modulator operates at a second sampling rate higher than the first sampling rate. The second continuous-time sigma-delta modulator has a continuous-time voltage controlled oscillator (VCO) quantizer, and a feedback loop coupled between the input and the output. The second continuous-time sigma-delta modulator is cascaded with the first continuous-time sigma-delta modulator. The summation element has inputs coupled to outputs of the first and second continuous-time sigma-delta modulators.

Abstract: A digital to analog converter including a current source for providing a master current, a first sub digital to analog converter coupled to the current source which generates a plurality of currents, and a second sub digital to analog converter coupled to at least one of the plurality of currents from the first sub digital to analog converter which generates a second plurality of currents. The digital to analog converter also includes an overlap adjustment circuit coupled with the second sub digital to analog converter which adds current. The digital to analog converter is configured to operate in a first mode for generating a sine wave with a first bit level accuracy and, when in the first mode, the overlap adjustment circuit adds no current.

Abstract: A digital to analog converter including a current source for providing a master current, a first sub digital to analog converter coupled to the current source which generates a plurality of currents, and a second sub digital to analog converter coupled to at least one of the plurality of currents from the first sub digital to analog converter which generates a second plurality of currents. The digital to analog converter also includes an overlap adjustment circuit coupled with the second sub digital to analog converter which adds current. The digital to analog converter is configured to operate in a first mode for generating a sine wave with a first bit level accuracy and, when in the first mode, the overlap adjustment circuit adds no current.

Abstract: A digital to analog converter including a current source for providing a master current, a first sub digital to analog converter coupled to the current source which generates a plurality of currents, and a second sub digital to analog converter coupled to at least one of the plurality of currents from the first sub digital to analog converter which generates a second plurality of currents. The digital to analog converter also includes an overlap adjustment circuit coupled with the second sub digital to analog converter which adds current. The digital to analog converter is configured to operate in a first mode for generating a sine wave with a first bit level accuracy and, when in the first mode, the overlap adjustment circuit adds no current.

Abstract: The embodiments described herein provide a digital-to-analog converter (DAC). The DAC implements a stepped return-to-zero (RZ) pulse scheme, where the DAC output includes the superposition of multiple time-offset RZ pulses. In one embodiment, the DAC includes a first switching element, a second switching element, a current source, and a current sink. The first switching element generates first RZ pulses, and the second switching element generates second RZ pulses, where the second RZ pulses are time-offset from the first RZ pulses. The first RZ pulses and second RZ pulses are combined to provide stepped RZ pulse output signal.

Abstract: A quantizer for an analog to digital converter has an input for receiving an analog input signal. A detector senses a common mode voltage component of the input signal. A reference voltage source produces a plurality of reference voltages. A voltage source biases the reference voltage source in response to the sensed common mode voltage component. Therefore, the common mode voltage in the input signal establishes the common mode voltage of the reference voltage source. A plurality of comparators are connected to the reference voltage source, wherein each of the plurality of comparators compares the input signal to one of the plurality of reference voltages and produces a output bit denoting a result of the comparing.

Abstract: A quantizer for an analog to digital converter has an input for receiving an analog input signal. A detector senses a common mode voltage component of the input signal. A reference voltage source produces a plurality of reference voltages. A voltage source biases the reference voltage source in response to the sensed common mode voltage component. Therefore, the common mode voltage in the input signal establishes the common mode voltage of the reference voltage source. A plurality of comparators are connected to the reference voltage source, wherein each of the plurality of comparators compares the input signal to one of the plurality of reference voltages and produces a output bit denoting a result of the comparing.

Abstract: A semiconductor device comprises a plurality of transistor mismatch circuits formed on a semiconductor wafer; and a characterization circuit formed on the semiconductor wafer. The characterization circuit is coupled to receive input provided by the absolute value circuits simultaneously which themselves receive inputs from the mismatch circuits simultaneously and is configured to output a standard deviation of mismatch between transistors in the mismatch circuits.

Abstract: A digital to analog converter including a current steering source and a master replica bias network. The current steering source includes a data current source providing a source current to a source node, a switch circuit operative to steer the source current to a selected one of first and second control nodes based on a data bit, a buffer circuit that buffers the source current between the first control node and a first current output node or between the second control node and a second current output node, and an activation current source provides activation current to the buffer circuit via the first and second control nodes. The master replica bias network replicates biasing of the buffer circuit relative to a replica control node and drives the buffer circuit to maintain the first control node, the second control node and the replica control node at a common master control voltage.