Analog Devices,inc.

Huseyin Dinc

Ahmed Mohamed Abdelatty Ali

Paritosh Bhoraskar

Ronald Bryce Gray, Iii

Scott Gregory Bardsley

Bryan Scott Puckett

Paridhi Gulati

William Thomas Boles

Andrew Stacy Morgan

Ahmed M A Ali

Michael Elliot

Ahmed Mohammed Abdelatty Ali

Aspects of the present disclosure include methods for operating discrete time circuits. A method in accordance with an aspect of the present disclosure may comprise sampling a first amplitude of a signal at a first time, sampling a second amplitude of the signal at a second time, comparing the first amplitude to the second amplitude, and adjusting a sampling time of the signal based at least in part on a difference between the first amplitude and the second amplitude.

Timing calibration techniques for discrete-time circuits

An example boosted switch driver circuit includes two branches. The first branch includes a first transistor. The second branch includes a second transistor and a level shifter circuit. One of the transistors is an N-type transistor and the other one is a P-type transistor. The circuit is configured to split an input clock signal between the first branch and the second branch, so that a portion of the input clock signal split to the first branch is provided to the first transistor, and a portion of the input clock signal split to the second branch is level-shifted by the level shifter circuit to generate a level-shifted input clock signal and the level-shifted input clock signal is provided to the second transistor. The circuit is further configured to combine an output of the first transistor and an output of the second transistor to generate an output clock signal.

Boosted switch drivers for high-speed signal switching

Background calibration techniques can effectively to correct for memory, kick-back, and order-dependent errors in interleaved switched-capacitor track-and-hold (T/H) circuits and amplifiers. The techniques calibrate for errors in both the track/sample phase and the hold-phase, and account for the effects of interleaving, buffer/amplifier sharing, incomplete resetting, incomplete settling, chopping, and randomization on the offset, gain, memory, and kick-back errors. Moreover, the techniques can account for order-dependent and state-dependent hold-phase non-linearities. By correcting for these errors, the proposed techniques improve the noise performance, linearity, gain/offset matching, frequency response (and bandwidth), and order-dependence errors. The techniques also help increase the speed (sample rate and bandwidth) and linearity of T/H circuits and amplifiers while simplifying the analog circuitry and clocking needed. These techniques comprehensively account for various memory, kick-back, and order-dependent effects in a unified framework.

Calibrating time-interleaved switched-capacitor track-and-hold circuits and amplifiers

One embodiment is an apparatus including a detector circuit electrically coupled between a signal source and a second circuit, the signal source generating a first signal, the detector circuit detecting a level of the first signal and generating a first control signal when the detected level of the first signal exceeds a first threshold value, and a clamping switch electrically coupled to receive the first control signal from the detector circuit, the clamping switch including a multi-terminal active device. The first control signal controls a state of the clamping switch such that the clamping switch clamps a level of a signal applied to the second circuit when the level of the first signal exceeds the first threshold value.

Signal level detection and overrange signal limiter and clamp for electronic circuits

A pipeline analog-to-digital converter (ADC) converts an analog input signal over several stages, where a stage generates a residue for the subsequent stage to digitize. The residue is generated by coarsely quantizing the analog input signal to generate a digital code, which is used to reconstruct the analog input signal, and the residue is the difference between the analog input signal and the reconstructed version of the analog input signal. The coarse quantization can have errors which are attributed to comparator offsets and bandwidth mismatch. To estimate the comparator offsets while being insensitive to bandwidth mismatch, peak and trough detectors are used to track maximum and minimum values of the residue or the output of the ADC over time, and an expected value estimating the comparator offset can be computed based on the maximum and minimum values. The expected value advantageously 'averages' out the bandwidth mismatch contribution to the offset.

Background estimation of comparator offset of an analog-to-digital converter

Circuits for generating voltage references are common in electronics. For example, these circuits are used in analog-to-digital converters, which convert an analog signal into its digital representation by comparing analog input signals against one or more voltage references provided by those circuits. In many applications, the speed and accuracy of such voltage references are very important. The speed of the voltage references is related to the physical properties of the devices in the circuit. The accuracy of the voltage reference is directly related to the circuit's ability to trim the full-scale voltage output. The present disclosure describes a fast and efficient reference buffer with a wide trim range which is particular suitable for submicron processes and high speed applications. The reference buffer comprises a plurality of diode-connected transistors, which can be selected to turn on or off using a controller to provide a wide trim range.

Reference buffer with wide trim range

A circuit may include one or more transistors connected directly to an output, and an inductance network. The inductance network may connect to a source node of at least one of the transistors, to compensate capacitance of the output. Thus, the response time of the circuit may decrease, and a non-dominant frequency response pole frequency of the circuit may increase.

High speed amplifier

A high frequency input signal comparator for optimizing group delay, reducing input frequency dependent offset and an offset auto-zeroing latch core are described. The comparator may include an isolation switch stage, and a latch core. The isolation switch stage may isolate latch core depending upon a control signal, thereby reducing input frequency dependent offset. The latch core may include a pair of inverters cross coupled via an impedance to one another. The latch core may include latch switches selected to attain a certain gain across the individual inverters comprising the latch core while resetting the latch core. The gain across the individual inverters during the acquire/reset phase may bootstrap the coupling impedances, thereby reducing loading and group delay at the input of the latch core. The coupling impedances may be designed to minimize or auto-zero statistical offset, thereby minimize input referred offset.

High frequency signal comparator for SHA-less analog-to-digital converters

A method and a corresponding device for reducing inter-channel coupling in a circuit having a plurality of channels includes injecting a randomly determined amount of dither into a first channel of a circuit having a plurality of channels, and after injecting the dither, obtaining an output signal of a second channel in the plurality of channels. A correlation value indicating a degree of correlation between the injected dither and the output signal is determined, and an amount of charge applied to the second channel due to cross-coupling with the first channel is reduced. The amount of the reduction is calculated as a function of the correlation value.

Method and device for reducing inter-channel coupling in interleaved and multi-channel ADCs

A method and device involve a circuit having a switched capacitor network that is switchably connected to an input signal. A randomly determined amount of dither is injected into a circuit having a switched capacitor network that is switchably connected to an input signal. After injecting the dither, at least one correlation value is determined. The correlation value(s) indicates a degree of correlation between the injected dither and an output of the circuit. Distortion caused by an amount of charge kicked back into the circuit when the switched capacitor network is reconnected to the input signal may then be reduced. The reduction is calculated as a function of the correlation value(s).

Reducing the effect of non-linear kick-back in switched capacitor networks

A process allows for the modification of the least-means-square (LMS) algorithm to remove perturbations associated with measured signals in an analog-to-digital converter (ADC). The process includes measuring the perturbations and determining a coefficient associated with the perturbations. The LMS algorithm is modified in accordance with whether a digital or an analog correction of the inter-stage error of a residue amplifier on the ADC is to be made.

Method for modifying the LMS algorithm to reduce the effect of correlated perturbations

An integrated circuit allows for the isolation of the input of an analog-to-digital converter (ADC) from a summing-node (SNS) algorithm. The integrated circuit contains a gating device that is controlled by bits of a flash analog-to-digital converter (ADC) to gate input samples to sub-ranges that are used by the SNS algorithm. A single sub-range is chosen to be used by the SNS algorithm.

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Greensboro, NC, United States of America

Huseyin Dinc